What types of wastewater are there?

• Direct discharges to surface waters will require an individual or general NPDES permit.
• Non-process wastewater is a concern for monitoring purposes when it dilutes pollutants in process wastewater.

Process wastewater. Process wastewater is “any water which, during manufacturing or processing, comes into direct contact with, or results from the production or use of any raw material, intermediate product, finished product, byproduct, or waste product,” and it can contain pollutants that could negatively affect surface waters. The National Pollutant Discharge Elimination System (NPDES) permit program sets limits on the type and amount of pollutants that can be discharged from industrial and commercial sources. Direct discharges to surface waters will require an individual or general NPDES permit.

An industrial source may also discharge to a municipal sewer system, which would be covered under the NPDES pretreatment program. Whether the facility is a direct or indirect discharger, it may also be covered by the effluent guidelines and standards.

Non-process wastewater. Non-process wastewater may also be regulated under the NPDES program. This type of wastewater comes from the use of water for activities such as using non-contact cooling water for heat exchange, sanitary, or cafeteria wastes. Non-process wastewater is a concern for monitoring purposes when it dilutes the concentration of pollutants of concern in process wastewater.

What pollutants are regulated in wastewater?

• Toxic pollutants are grouped into organics and metals.
• Nonpoint sources are diffuse sources of pollution while point sources are specific points of discharge.

The Environmental Protection Agency (EPA) identifies conventional pollutants as those that may be controlled through effluent guidelines. These pollutants are contained in the sanitary wastes of households, businesses, and industries. Conventional pollutants include:

• Biochemical oxygen demand (BOD),
• Total suspended solids (TSS),
• Fecal coliform,
• Oil and grease,
• pH, and
• Other pollutants as determined by EPA.

EPA identifies 65 pollutants and classes of pollutants as toxic pollutants; of those, EPA designates 126 specific substances as “priority” toxic pollutants, and the list of priority toxic pollutants can be found at 40 CFR 423, Appendix A. Toxic pollutants are particularly harmful to animal or plant life, and they are primarily grouped into:

• Organics (including pesticides, solvents, polychlorinated biphenyls (PCBs), and dioxins); and
• Metals (including lead, silver, mercury, copper, chromium, zinc, nickel, and cadmium).

All other pollutants are classified as nonconventional pollutants. These are any additional substances that are not conventional or toxic that may require regulation, including nutrients such as nitrogen and phosphorus.

Nonpoint sources vs. point sources

Think of nonpoint sources (NPS) of pollution as “diffuse sources” of pollution. The discharge does not originate from a specific point, outfall, pipe, or other specific place. It can result from land runoff or seepage or be deposited from the atmosphere. Snowmelt that picks up contaminants as it moves over and through the ground can be a type of NPS pollution. Eventually, the runoff deposits contaminants into surface waters, such as lakes, rivers, wetlands, and coastal waters. Examples of NPS include:

• Excess fertilizers, herbicides, and pesticides from farms and lawns;
• Oil, grease, and toxic chemicals from industrial sites and energy production;
• Sediment from improperly managed construction sites;
• Crop lands, forests, and eroding streambanks;
• Bacteria and nutrients from animal waste and faulty septic systems; and
• Atmospheric deposits from hydromodification (e.g., dams).

Point sources, on the other hand, are specific “points” of discharge. Common points of discharge include pipes, tunnels, channels, etc. Typical point sources include factories and sewage treatment plants. Sources may discharge one or more pollutants, or “effluents,” to a surface water. Some sources discharge directly into a waterbody, while others treat the effluent before releasing it. In addition, sources may send their wastewater to a sewage treatment plant for treatment.

How are wastewater discharges permitted?

• NPDES permits consist of at least five sections.
• Most states run their own Pollutant Discharge Elimination System permitting programs.

The permitting program for wastewater is the National Pollutant Discharge Elimination System (NPDES), which regulates discharges of pollution from point sources and is designed to limit the amount of pollutants that reach waters of the United States. The NPDES is responsible for issuing, modifying, revoking and reissuing, terminating, monitoring and enforcing permits, and imposing and enforcing pretreatment requirements, under the Clean Water Act (CWA). While NPDES is a federal program, most states run their own Pollutant Discharge Elimination System permitting programs.

Discharge of a pollutant is defined as:

• Any addition of any “pollutant” or combination of pollutants to “waters of the United States” from any “point source,” or
• Any addition of any pollutant or combination of pollutants to the waters of the shoreline or the ocean from any point source other than a vessel or other floating craft which is being used as a means of transportation.
• This definition includes additions of pollutants into waters of the United States from: surface runoff which is collected or channeled by humans; discharges through pipes, sewers, or other conveyances owned by a state, municipality, or other person which do not lead to a treatment works; and discharges through pipes, sewers, or other conveyances, leading into privately owned treatment works. This term does not include an addition of pollutants by any “indirect discharger.”

A general permit is an NPDES permit issued under 122.28 authorizing a category of discharges under the CWA within a geographical area. The restriction on quantities, discharge rates, and concentrations of pollutants which are discharged from point sources into waters of the United States, shorelines, or the ocean are known as “effluent limitations.”

NPDES permits cover a wide range of industrial activities. The regulations related to the NPDES program are found in 40 CFR:

• Part 121 — State certification
• Part 122 — The federal NPDES permit program
• Part 123 — State program requirements
• Part 124 — Procedures for decision making
• Part 125 — Technology standards
• Part 129 — Toxic pollutant effluent standards
• Part 130 — Water quality planning and management
• Part 131 — Water quality standards
• Part 133 — Secondary treatment standards
• Part 135 — Citizen suits
• Part 136 — Analytical procedures
• Part 257 — State sludge disposal regulations
• Part 401 — General provisions for effluent limitations guidelines and standards
• Part 403 — General pretreatment regulations
• Parts 405-471 — Effluent guidelines
• Part 501 — State sewage sludge management program requirements
• Part 503 — Standards for use or disposal of sewage sludge

NPDES permits consist of at least five sections.

1. Cover page: Lists the name and location of the facility, a statement authorizing the discharge, and a listing of the specific locations for which a discharge is authorized.
2. Effluent limitations: The primary mechanism for controlling discharges of pollutants to receiving waters.
3. Monitoring and reporting requirements: Used to characterize wastestreams and receiving waters, evaluate wastewater treatment efficiency, and determine compliance with permit conditions.
4. Special conditions: Conditions developed to supplement numeric effluent limitations. Examples include additional monitoring activities, special studies, best management practices (BMPs), and compliance schedules.
5. Standard conditions: Pre-established conditions that apply to all NPDES permits and delineate the legal, administrative, and procedural requirements of the NPDES permit.

Fact sheet: The Environmental Protection Agency (EPA) says that in addition to the five sections listed above, a permit will always be accompanied by a fact sheet or statement of basis explaining the rationale for the permit conditions.

Agency roles and responsibilities

• Different federal resource agencies have various responsibilities regarding section 404 permitting.

The roles and responsibilities of the federal resource agencies regarding section 404 permitting differ in scope.

U.S. Environmental Protection Agency (EPA)

• Develops and interprets policy, guidance, and environmental criteria used in evaluating permit applications;
• Determines scope of geographic jurisdiction and applicability of exemptions;
• Approves and oversees state and tribal assumption;
• Reviews and comments on individual permit applications;
• Has authority to prohibit, deny, or restrict the use of any defined area as a disposal site (Section 404(c));
• Can elevate specific cases (Section 404(q)); and
• Enforces Section 404 provisions.

U.S. Army Corps of Engineers

• Administers day-to-day program, including individual and general permit decisions;
• Conducts or verifies jurisdictional determinations;
• Develops policy and guidance; and
• Enforces Section 404 permit provisions.

U.S. Fish and Wildlife Service and National Marine Fisheries Service

• Evaluates impacts on fish and wildlife of all new federal projects and federally permitted projects, including projects subject to the requirements of Section 404 (pursuant to the Fish and Wildlife Coordination Act); and
• Evaluates specific cases or policy issues under Section 404(q).

The Clean Water Rule and WOTUS

• WOTUS was intended to define the scope of waters that are covered by the federal CWA.
• Intermittent features, unlike ephemeral features, may be considered waters of the United States.

On June 29, 2015, the Environmental Protection Agency (EPA) and the U.S. Army Corps of Engineers published the “Clean Water Rule: Definition of Waters of the United States,” also known as WOTUS. The rule was intended to define the scope of waters that are covered by the federal Clean Water Act (CWA).

The Clean Water Rule did not establish any regulatory requirements. Instead, it attempted to clarify the scope of “waters of the U.S.” consistent with the CWA, Supreme Court precedent, and science. This definition of WOTUS matters because many regulatory programs that fall under the scope of the federal Clean Water Act only apply when there is the possibility of impacting a water of the United States.

CWA programs that rely on the definition of waters of the U.S. include:

• The National Pollutant Discharge Elimination System (NPDES)
• Section 404 permit program for discharge of dredged materials (wetlands permitting)
• Oil spill prevention and response programs (Spill Prevention, Control, and Countermeasure (SPCC) and Facility Response Plans (FRPs))

The rule has had a rocky history over the years marked by shifting definitions, executive orders, legal appeals, and Supreme Court rulings. On January 23, 2020, EPA and the U.S. Army Corps of Engineers (ACOE) finalized the Navigable Waters Protection Rule to define waters of the United States. However, in August 2021, EPA and ACOE announced they have stopped implementation of the Navigable Waters Protection Rule as a result of an Arizona District Court case. The ruling has reprioritized previously announced plans to rework the definition of WOTUS and replace the Navigable Waters Protection Rule.

For the time being, the agencies will be using the pre-2015 interpretation of WOTUS found in 40 CFR 230.3(s):

1. All waters which are currently used, or were used in the past, or may be susceptible to use in interstate or foreign commerce, including all waters which are subject to the ebb and flow of the tide;
2. All interstate waters including interstate wetlands;
3. All other waters such as intrastate lakes, rivers, streams (including intermittent streams), mudflats, sandflats, wetlands, sloughs, prairie potholes, wet meadows, playa lakes, or natural ponds, the use, degradation or destruction of which could affect interstate or foreign commerce including any such waters:
   1. Which are or could be used by interstate or foreign travelers for recreational or other purposes; or
   2. From which fish or shellfish are or could be taken and sold in interstate or foreign commerce; or
   3. Which are used or could be used for industrial purposes by industries in interstate commerce;
4. All impoundments of waters otherwise defined as waters of the United States under this definition;
5. Tributaries of waters identified in paragraphs (s)(1) through (4) of this section;
6. The territorial sea;
7. Wetlands adjacent to waters (other than waters that are themselves wetlands) identified in paragraphs (s)(1) through (6) of this section; waste treatment systems, including treatment ponds or lagoons designed to meet the requirements of CWA (other than cooling ponds as defined in 40 CFR 423.11(m) which also meet the criteria of this definition) are not waters of the United States.

Waters of the United States do not include prior converted cropland. Notwithstanding the determination of an area’s status as prior converted cropland by any other federal agency, for the purposes of the Clean Water Act, the final authority regarding Clean Water Act jurisdiction remains with EPA.

A note on ephemeral vs. intermittent

Ephemeral means surface water flowing or pooling only in direct response to a rain or snow event. Ephemeral features are not waters of the United States.

Intermittent means surface water flowing continuously during certain times of the year and more than in direct response to a rain or snow event. Intermittent features may be waters of the United States.

Stormwater discharges and permitting

• In addition to industrial wastewater discharges, NPDES also applies to stormwater discharges from industrial facilities.

In addition to industrial wastewater discharges, the National Pollutant Discharge Elimination System (NPDES) also applies to stormwater discharges from industrial facilities. Facilities with the following types of stormwater discharges, among others, must apply for a NPDES permit:

• A discharge associated with industrial activity, including construction activities;
• A discharge from a large or medium municipal storm sewer system; or
• A discharge which the Environmental Protection Agency (EPA) or the state determines to contribute to a violation of a water quality standard or is a significant contributor of pollutants to waters of the United States.

Across the nation, many waterbodies are listed as impaired because of pollutants found in stormwater. These pollutants include sediment, pathogens, nutrients, and metals. If a waterbody is impaired, the state or federal EPA must set a Total Maximum Daily Load (TMDL) for a pollutant which identifies the total pollutant load the waterbody can handle before it cannot meet its water quality standards. Stormwater TMDLs are implemented through the NPDES stormwater permitting system. The program covers most municipalities and most construction activities.

Watersheds are affected by construction activities because land development converts natural areas into “impervious cover.” Blacktopped parking lots, buildings, streets, and other impervious surfaces prevent water from soaking into the ground or being taken up by plants. The more impervious cover an area has, the more stormwater runoff will find its way into nearby waterbodies. The increase in volume and rate of runoff can erode stream channels and transport more pollutants into streams, lakes, and other bodies of water. Industries and construction companies must meet specific effluent limits for stormwater runoff in their NPDES permits.

Stormwater Pollution Prevention Plans (SWPPPs)

• Baseline pollution prevention plans have two major objectives.

Companies and municipalities who must file general stormwater permits must complete and implement Stormwater Pollution Prevention Plans (SWPPPs). Although the plans need not be submitted to the Environmental Protection Agency (EPA), they must be on file, and on request be given to an EPA inspector.

Baseline pollution prevention plans have two major objectives. They must:

1. Identify potential sources of pollution; and
2. Describe and ensure practices to reduce pollutants in stormwater discharges. These objectives can be broken down as follows:

Source Identification Information Plans

Source Identification Information Plans must include the following information to assist in evaluating pollutant sources:

• Site drainage map.
• Estimate of the area of impervious surfaces, and the total area drained by each outfall.
• Narrative description of specified features that may impact the pollution potential of a discharge.
• List of significant spills and leaks of toxic or hazardous pollutants that occurred at the facility after the effective date of the permit.
• Prediction of the direction of flow, and an estimate of the types of pollutants that may be present in stormwater discharges associated with industrial activity, prediction of the direction, rate of flow and total quantity of pollutants that may be present in stormwater discharges associated with industrial activity.
• Summary of existing sampling data describing pollutants in stormwater discharges.

Best management practices and program elements to reduce pollutants

Best management practices and program elements to reduce pollutants, at a minimum, must provide information regarding:

• Pollution prevention committee,
• Risk identification and assessment/material inventory,
• Preventive maintenance,
• Good housekeeping,
• Spill prevention and response procedures,
• Traditional stormwater management,
• Sediment and erosion prevention,
• Employee training,
• Visual inspections,
• Record keeping and internal reporting procedures, and
• Certification that stormwater discharges have been tested for the presence of non-stormwater pollution sources.

What are the different public water system classifications?

• SDWA does not regulate private wells that serve fewer than 25 individuals.
• Under SDWA, states can apply for “primacy” in implementing their drinking water programs.
• EPA has defined three types of public water systems.

Every day, millions of Americans access their drinking water from public water systems. These systems may be publicly or privately owned and are defined as a system that provides public piped drinking water that has at least 15 service connections or that serves an average of at least 25 individuals daily for 60 days out of the year. The Safe Drinking Water Act (SDWA) does not regulate private wells that serve fewer than 25 individuals.

While usually safe, a number of situations could pose health risks to the public, including drinking water that is not properly treated or disinfected, or drinking water that travels through an improperly maintained distribution system. In addition, contaminants that pose a threat to drinking water include:

• Improperly disposed chemicals
• Animal wastes
• Pesticides
• Human wastes
• Wastes injected deep underground
• Naturally occurring substances

Under SDWA, states can apply for “primacy” in implementing their drinking water programs. States that are granted primacy must show that their standards are at least as stringent as the Environmental Protection Agency’s (EPA’s), and that they can meet those standards. All states and territories besides Wyoming and the District of Columbia have received primacy.

States with primacy (or EPA acting as the primacy agent) must ensure all water systems do the following:

1. Test for contaminants.
2. Review plans for water system improvements.
3. Conduct on-site inspections and sanitary surveys.
4. Provide training and technical assistance.
5. Enforce the standards.

There are over 151,000 public water systems in the United States. EPA classifies these water systems according to the number of people they serve, the source of their water, and whether they serve the same customers year-round or on an occasional basis.

Classifications

EPA has defined three types of public water systems:

• Community Water System: A public water system that supplies water to the same population year-round.
• Non-Transient Non-Community Water System: A public water system that regularly supplies water to at least 25 of the same people at least six months per year. Some examples are schools, factories, office buildings, and hospitals which have their own water systems.
• Transient Non-Community Water System: A public water system that provides water in a place such as a gas station or campground where people do not remain for long periods of time.

Is a business a public drinking water system?

The federal definition of a public water system is a system that provides piped water for human consumption, if the system has at least 15 service connections or “regularly serves” an average of at least 25 individuals daily at least 60 days out of the year. “Regularly serves,” means the water is available for consumption, even if it is not actually being consumed.

If the facility provides drinking water to employees and visitors, the facility may meet the above description as a public water system. This means the facility must monitor the quality of the water.

Note: If a facility receives drinking water from a municipality, this requirement does not apply. If the business gets its drinking water from a private well, the business must comply with the drinking water regulations.

National primary drinking water regulations

• States must conduct sanitary surveys every three years for community water systems and every five years for non-community water systems.
• Public water systems must perform assessments to identify sanitary defects and subsequently take action to correct them.

The national primary drinking water regulations (NPDWRs) are the legally enforceable standards that apply to public water systems. Find the list of all the contaminants and standards — including organic chemicals, inorganic chemicals, disinfectants, disinfection byproducts, microorganisms, and radionuclides — as well as the “maximum contaminant levels” (MCLs) at www.epa.gov/ground-water-and-drinking-water/national-primary-drinking-water-regulations.

Under the Safe Drinking Water Act (SDWA), the Environmental Protection Agency (EPA) is required to set “maximum contaminant level goals” (MCLGs) for all the known or anticipated contaminants to drinking water. EPA works toward achieving these non-enforceable goals whenever possible.

On April 10, 2024, EPA announced the final National Primary Drinking Water Regulation for six PFAS. EPA established the MCLs, for six PFAS in drinking water: PFOA, PFOS, PFHxS, PFNA, and HFPO-DA as contaminants with individual MCLs, and PFAS mixtures containing at least two or more of PFHxS, PFNA, HFPO-DA, and PFBS using a Hazard Index MCL to account for the combined and co-occurring levels of these PFAS in drinking water. EPA also finalized health-based, non-enforceable MCLGs for these PFAS. 

The final rule requires:

• Public water systems must monitor for these PFAS and have three years to complete initial monitoring (by 2027), followed by ongoing compliance monitoring. Water systems must also provide the public with information on the levels of these PFAS in their drinking water beginning in 2027.
• Public water systems have five years (by 2029) to implement solutions that reduce these PFAS if monitoring shows that drinking water levels exceed these MCLs.
• Beginning in five years (2029), public water systems that have PFAS in drinking water which violates one or more of these MCLs must take action to reduce levels of these PFAS in their drinking water and must provide notification to the public of the violation.

Groundwater Rule

Published in 2006, the rule was established to protect against microbial contamination of drinking water systems that use groundwater sources. Under the rule, states must conduct sanitary surveys every three years for community water systems and every five years for non-community water systems. The rule contains additional requirements such as hydro-geologic sensitivity assessment and enhanced source water monitoring for certain systems.

Surface Water Treatment Rule

This rule establishes filtrations and disinfection requirements to guard against waterborne diseases caused by viruses such as Legionella and Giardia Lamblia.

Arsenic Rule

EPA set a standard of 10 parts per billion (ppb) in January 2001 (down from 50 ppb). Water systems were required to comply with this standard by January 2006 including reporting on the Consumer Confidence Report.

Radon Rule

EPA established standards for radon in drinking water in November 1999. The rule applies to water systems that use ground water or a mixture of ground water and surface water. A major provision of the proposal is the option to implement a multimedia mitigation program.

Radionuclides Rule

EPA updated standards for radionuclides in drinking water in December 2000. The Agency also set a new standard for uranium. The standards are: combined radium 226/228 (5 pCi/L); beta emitters (4 mrems); gross alpha standard (15 pCi/L); and uranium (30 μg/L).

Revised Total Coliform Rule (RTCR)

When coliform bacteria show up in drinking water, it’s an indication that the treatment system is not working or that there are problems in the distribution system. The Revised Total Coliform Rule (RTCR) establishes a maximum contaminant level (MCL) for E. coli and uses E. coli and total coliforms to initiate a “find and fix” approach to address fecal contamination that could enter into the distribution system. It requires public water systems to perform assessments to identify sanitary defects and subsequently take action to correct them.

Lead and Copper Rule

• The water system must inform the public any time that lead and copper in the drinking water go over the set limits and outline steps they should take to protect health.
• Final revisions to the LCR include six actions to address lead contamination in drinking water.

In 1991, EPA published the Lead and Copper Rule (LCR) to minimize lead and copper in drinking water. The rule established maximum contaminant level goals (MCLG) of zero for lead in drinking water and a treatment technique to reduce corrosion within the distribution system. The rule was revised in 2007.

Lead and copper enter drinking water mainly through corroding plumbing materials containing lead and copper. Exposure to either element can cause a variety of health problems ranging from stomach distress to brain damage.

In 2011, changes to the Safe Drinking Water Act reduced the maximum allowable lead content — that is, content that is considered “lead-free” — to be a weighted average of 0.25 percent calculated across the wetted surfaces of pipes, pipe fittings, plumbing fittings, and fixture and 0.2 percent for solder and flux.

The water system must also inform the public any time that lead and copper in the drinking water go over the set limits and outline steps they should take to protect their health.

Effective March 16, 2021, final revisions to the LCR include several actions to address lead contamination in drinking water, including:

1. Identifying areas most impacted. All water systems must complete and maintain a lead service line inventory and collect tap samples from homes with lead service lines if lead is present in the distribution system. To reduce elevated levels of lead in certain locations, all water systems must engage in a “find-and-fix” process to identify the causes of these elevated levels as well as take potential actions to reduce lead levels.
2. Strengthening treatment requirements. There are expanded requirements for corrosion control treatment (CCT) based on tap sampling results with a new trigger level of 10 µg/L. At this trigger level, systems that currently treat for corrosion are required to re-optimize their existing treatment. Systems that do not currently treat for corrosion will be required to conduct a corrosion control study so that the system is prepared to respond quickly if necessary. (EPA says flexibility is important for small systems so that they can protect public health by taking the treatment actions that make sense for their communities.) Alternatives to CCT for small systems including Point-of-Use (POU) treatment and replacement of lead bearing plumbing materials.
3. Systematically replacing lead service lines. Water systems with high lead levels must initiate lead service line removal. All water systems with lead service lines or “lead status unknown” service lines must create a lead service line removal plan by the rule compliance date. Systems that are above the trigger level of 10 mg/L, but at or below the lead action level of 15 mg/L, must conduct replacements at a goal rate approved by the state, and, systems that are above the action level, must annually replace a minimum of three percent per year, based upon a two-year rolling average of the number of known or potential lead service lines in the inventory at the time the action level exceedance occurs. Systems cannot end their replacement program until they demonstrate lead levels less than the action level for two years. Only full lead service line replacements will be counted toward the required rate, not partials and not “in lieu of” samples. Finally, water systems must communicate with homes with lead service lines annually and replace the water system-owned portion of a lead service line when a customer chooses to replace their customer-owned portion of the line within 45 days with the ability to have up to 180 days with notification to the state.
4. Increasing sampling reliability. Tap sample site selection must focus on sites with lead service lines (where present). Systems must collect fifth-liter samples that are representative of water that has been in the lead service line for several hours. (This will provide better information on the highest concentration of lead in drinking water.) Tap sampling instructions may not call for pre-stagnation flushing or the cleaning or removing of faucet aerators and must include a requirement that tap samples be collected in bottles with a wide-mouth configuration.
5. Improving risk communication. Systems must notify consumers of a system-wide action level exceedance within 24 hours. For individual tap samples that exceed 15 µg/L, systems must notify the individual consumer within three days. Public notifications must consistently use clear and concise language and all public education materials must include the health effects of exposure to lead in drinking water. Systems must conduct regular outreach to customers with lead service lines. Systems must make their lead service lines inventory publicly available and must notify occupants of homes with lead service lines every year about their lead service lines, drinking water exposure risks, and mitigation options, including removal.
6. Protecting children in schools. Community water systems must test for lead in drinking water in schools and childcare facilities. Systems must conduct drinking water sampling at each elementary school and each childcare facility they serve over no more than five years, testing 20 percent of the facilities they serve each year.

National secondary drinking water regulations and UCMR

• States may choose to adopt secondary standards but are not mandated to do so by the EPA.
• Public water systems must collect occurrence data for contaminants that may be present in drinking water but are not yet subject to EPA’s drinking water standards set under SDWA.

National secondary drinking water regulations are non-enforceable guidelines that apply to contaminants that may have cosmetic or aesthetic effects at certain exposures in drinking water. These effects include tastes, odors, or colors, or skin and teeth discolorations.

States may choose to adopt the secondary standards but are not mandated to do so by the Environmental Protection Agency (EPA).

Unregulated Contaminant Monitoring Rule (UCMR)

On December 20, 2016, EPA finalized a rule that requires public water systems to collect occurrence data for contaminants that may be present in drinking water but are not yet subject to EPA’s drinking water standards set under the Safe Drinking Water Act (SDWA).

The rule identifies 11 analytical methods to support water systems monitoring for a total of 30 chemical contaminants (nine cyanotoxins and one cyanotoxin group; two metals; eight pesticides plus one pesticide manufacturing byproduct; three brominated haloacetic acid disinfection byproduct groups; three alcohols; and three semivolatile organic chemicals).

UIC Program

• The UIC Program regulates the construction, operation, permitting, and closure of injection wells that place fluids underground for storage or disposal.
• There are six types of injection wells.
• States and tribes may apply for primary enforcement responsibility to implement the UIC Program.

The Underground Injection Control (UIC) Program regulates the construction, operation, permitting, and closure of injection wells that place fluids underground for storage or disposal. These fluids may be water, wastewater, saltwater, or water that is mixed with chemicals. The Environmental Protection Agency (EPA) defines injection wells as:

• A bored, drilled, or driven shaft, or a dug hole that is deeper than it is wide;
• An improved sinkhole; or
• A subsurface fluid distribution system.

There are six types of injection wells:

• Class I - Industrial and municipal waste disposal wells
• Class II - Oil and gas related wells
• Class III - Mining wells
• Class IV - Shallow hazardous and radioactive injection wells
• Class V - Shallow non-hazardous injection wells
• Class VI - Geologic sequestration wells

Injection wells have a range of uses including:

• Storing carbon dioxide
• Disposing of waste
• Enhancing oil production
• Mining
• Preventing saltwater intrusion

Definition of USDW

An underground source of drinking water (USDW) is an aquifer or a part of an aquifer that is currently used as a drinking water source. A USDW may also be ground water needed as a drinking water source in the future. A USDW is defined in the Code of Federal Regulations (40 CFR 144.3) as:

“An aquifer is a geological formation or group of formations or part of a formation that is capable of yielding a significant amount of water to a drinking water well or spring.

• Which supplies any public water system; or
• Which contains a sufficient quantity of ground water to supply a public water system; and
  • Currently supplies drinking water for human consumption; or
  • Contains fewer than 10,000 mg/l total dissolved solids; and which is not an exempted aquifer.

The UIC Program implements this protective mandate through the UIC regulations.

Protecting drinking water resources

The UIC Program protects USDWs from endangerment by setting minimum requirements for injection wells. All injection must be authorized under either:

• General rules, or
• Specific permits.

Injection well owners and operators may not:

• Site, construct, operate, maintain, convert, plug, or abandon wells
• Conduct any other injection activity that endangers USDWs

The purpose of the UIC requirements is to ensure that either:

• Injected fluids stay within the well and the intended injection zone, or
• Fluids that are directly or indirectly injected into a USDW do not cause a public water system to violate drinking water standards or otherwise adversely affect public health.

EPA regulates UICs under the Safe Drinking Water Act (SDWA) to protect public health by preventing injection wells from contaminating underground sources of drinking water. A technical overview of UIC regulations is available on EPA’s website.

Regulating agency

Injection wells are overseen by either a state or tribal agency or one of EPA’s regional offices. States and tribes may apply for primary enforcement responsibility to implement the UIC Program. This is called primacy.

In general, state and tribal programs must meet minimum federal UIC requirements to gain primacy. If a state or tribe does not obtain primacy, EPA implements the program directly through one of its regional offices.

EPA has delegated primacy for all well classes to 33 states and three territories. EPA shares responsibility in seven states. EPA implements a program for all well classes in 10 states, two territories, and the District of Columbia, and for most tribes.

Well maintenance

• Hich-capacity wells require annual reporting on the amounts of water withdrawn from the ground and may require a permit to operate.
• SDWA sets up barriers against pollution to ensure that drinking water is safe.

Public water systems are responsible for maintaining the facility in a safe and sanitary condition. Businesses need to use a federal or state certified professional for well and pump maintenance and a master plumber for any work done on the water distribution system.

Prevent well contamination

Preventing contamination is easier and less expensive than having to deal with the aftermath of a contaminated well. The Environmental Protection Agency (EPA) suggests working with neighboring businesses and landowners or local governmental entities to remove or mitigate potential sources of contamination that could affect more than just the well.

Tips on preventing contamination

Protect the water supply by carefully managing activities near the water source. For businesses and households using a well, this includes keeping contaminants away from sinkholes and the well itself. Keep hazardous chemicals out of septic systems.

• Slope the area around the well to drain surface runoff away from the well.
• Install a well cap or sanitary seal to prevent unauthorized use of, or entry into, the well.
• Keep accurate records of well maintenance, such as disinfection or sediment removal, that may require the use of chemicals in the well.
• Hire a certified well driller for any new well construction, modification, or abandonment and closure.
• Avoid mixing or using pesticides, fertilizers, herbicides, degreasers, fuels, and other pollutants near the well.
• Do not dispose of wastes in dry wells or in abandoned wells.
• Do not cut off the well casing below the land surface.
• Pump and inspect septic systems as often as recommended by the local health department.
• Never dispose of harsh chemicals, solvents, petroleum products, or pesticides in a septic system or dry well.
• Periodically inspect exposed parts of the well for problems such as:
  • Cracked, corroded or damaged well casing
  • Broken or missing well cap
  • Settling and cracking of surface seals
• Regularly check the integrity of any above ground and underground storage tanks that hold home heating oil, diesel, or gasoline on the property.
• Check with the local health department or environmental agency to ensure activities and industry on or near the property are set a safe distance from the facility’s well.

High-capacity wells

Public water systems with the capacity to pump 70 gallons per minute or more are considered to be high-capacity wells. These wells need additional approvals before construction. They require annual reporting on the amounts of water withdrawn from the ground and may require a permit to operate (along with annual fees).

Pollution barriers

Safe Drinking Water Act (SDWA) sets up barriers against pollution to ensure that drinking water is safe. These include:

• Source water protection (Water systems treat and test their water on a frequent basis for specified contaminants and report test results to the states.)
• Treatment.
• Distribution system integrity.
• Public information. (If a water system does not meet the standards it must notify its customers. Many suppliers are also required to submit annual reports to customers.)

Levels of control

• National regulations for industrial wastewater discharges set technology-based numeric limitations for specific pollutants at several levels of control.
• The levels of control apply to different types of regulated sites and pollutants.

National regulations for industrial wastewater discharges set technology-based numeric limitations for specific pollutants at several levels of control: BPT, BCT, BAT, NSPS, PSNS or PSES. Effluent limitations are based on the performance of specific technologies, but the regulations do not require use of specific control technology.

BPT — Best Practicable Control Technology Currently Available

The Environmental Protection Agency (EPA) establishes BPT effluent limitations based on the average of the best performance of facilities within the industry of various ages, sizes, processes or other common characteristics. Where existing performance is uniformly inadequate, BPT may reflect higher levels of control than currently in place in an industrial category if the Agency determines that the technology can be practically applied.

BCT — Best Conventional Pollutant Control Technology

BCT addresses conventional pollutants from existing industrial point sources. In addition to considering the other factors specified in Clean Water Act (CWA) 304(b)(4)(B), EPA establishes BCT limitations after consideration of a two-part “cost-reasonableness” test.

BAT — Best Available Technology Economically Achievable

In general, BAT represents the best available economically achievable performance of plants in the industrial subcategory or category.

NSPS — New Source Performance Standards

NSPS applies to direct dischargers. NSPS reflect effluent reductions that are achievable based on the “best available demonstrated control technology.” New sources can install the best and most efficient production processes and wastewater treatment technologies. As a result, NSPS should represent the most stringent controls attainable through the application of the best available demonstrated control technology for all pollutants (i.e., conventional, non-conventional, and priority pollutants). In establishing NSPS, EPA is directed to take into consideration the cost of achieving effluent reduction and any non-water quality environmental impacts and energy requirements.

PSNS — Pretreatment Standards for New Sources

PSNS are national, uniform, technology-based standards that apply to dischargers to publicly owned treatment works (POTWs) from specific industrial categories (i.e., indirect dischargers).

PSES — Pretreatment Standards for Existing Sources

Like PSNS, PSES are national, uniform, technology-based standards that apply to indirect dischargers. They are designed to prevent the discharge of pollutants that pass through, interfere with, or are otherwise incompatible with the operation of POTWs.

These levels of control are supplemented by best management practices (BMPs), defined as a permit condition used in place of, or in conjunction with effluent limitations, to prevent or control the discharge of pollutants. BMPs may include a schedule of activities, prohibition of practices, maintenance procedure, or other management practice.

The levels of control apply to different types of regulated sites and pollutants:

For a numeric limit to be enforceable, an approved analytical method — a test procedure to measure the parameter — must be available. CWA 304(h) directs EPA to promulgate analytical methods, and these are published at 40 CFR Part 136. EPA-approved methods published by other organizations are also listed in Part 136.

Effluent guidelines

• Effluent guidelines are wastewater discharge standards based on the types of contaminants that are common for an industry.

National Pollutant Discharge Elimination System (NPDES) permits use effluent limitations as the main way to control discharges of pollutants to receiving waters. In setting the limits, the permit writer considers both the technology available to control the pollutants and limits that protect the water quality standards of the receiving water.

The Environmental Protection Agency (EPA) establishes effluent limitations guidelines and standards for different industrial categories. The guidelines are based on the degree of pollutant reduction attainable by an industrial category through the application of pollutant control technologies.

Effluent guidelines program plans

Effluent guidelines are wastewater discharge standards based on the types of contaminants that are common for a particular industry. The regulations are technology-based and encompass the greatest pollutant reductions that are economically achievable for an industry.

The effluent guideline standards for direct dischargers are incorporated into their NPDES permit issued by federal EPA or their state. Indirect dischargers must also obtain permits and may have to take other control measures.

Clean Water Act (CWA) 304(b) requires EPA to annually review and, if appropriate, revise effluent guidelines. EPA publishes a plan every other year, establishing a schedule for annual review and revision, pursuant to 304(m). This plan also identifies industries discharging more than trivial amounts of toxic or nonconventional pollutants, such as nutrients, for which the Agency has not yet promulgated effluent guidelines. EPA is required to establish a schedule for completing effluent guidelines for these industries within three years.

Effluent limitations

• TBELs in NPDES permits require a minimum level of treatment of pollutants for point source discharges while allowing the discharger to use any available control technique to meet the limits.

Technology-based effluent limitations

Technology-based effluent limitations (TBELs) in National Pollutant Discharge Elimination System (NPDES) permits require a minimum level of treatment of pollutants for point source discharges based on available treatment technologies, while allowing the discharger to use any available control technique to meet the limits. For industrial (and other non-municipal) facilities, technology-based effluent limits are derived by:

• Using national effluent limitations guidelines and standards established by the Environmental Protection Agency (EPA), and/or
• Using best professional judgement (BPJ) on a case-by-case basis in the absence of national guidelines and standards.

Water quality-based effluent limitations and TMDLs

The Clean Water Act (CWA) establishes a process for states to identify waters within their boundaries where implementing technology-based controls isn’t enough to achieve water quality standards. States establish a priority ranking of these waters and, for the priority waters, develop Total Maximum Daily Loads (TMDLs). A TMDL identifies the amount of a specific pollutant or property of a pollutant, from point, nonpoint, and natural background sources, including a margin of safety, that may be discharged to a water body and still ensure that the water body attains water quality standards. The allocations of pollutant loadings to point sources are called wasteload allocations.

Effluent limits in NPDES permits must be consistent with the assumptions used to derive the wasteload allocations. Also, in the absence of a TMDL, permitting authorities still must assess the need for effluent limits based on water quality standards and, where necessary, develop appropriate wasteload allocations and effluent limits. This analysis could be done for an entire watershed or separately for each individual discharge.

Permit writers have to consider the potential impact of every proposed surface water discharge on the quality of the receiving water. If TMDLs are not sufficient to meet the water quality standards in the receiving water, the CWA and NPDES regulations require that the permit writer develop more stringent, water quality-based effluent limits.

Water quality planning and management

The regulations governing the TMDL program are found at 40 CFR 130.7. Once a state has identified its impaired waters, it must:

• Set up TMDLs;
• Set priorities for developing the loads;
• Establish loads for segments identified, including water quality monitoring, modeling, data analysis, calculation methods, and the list of pollutants to be regulated;
• Submit the list of segments identified, priority ranking, and loads established to EPA for approval;
• Incorporate the approved loads into the state’s water quality management plans and NPDES permits; and
• Describe the process in its State Continuing Planning Process.

Discharge reporting

• General permits are written to cover one or more categories of discharges, disposal practices, or types of facilities in a geographic area.
• NPDES general permits typically rely on the submission of NOI documents.
• Facilities must use NAICS codes and SIC codes that reflect the products or services provided by the facility when applying for a NPDES permit.

The Clean Water Act (CWA) and National Pollutant Discharge Elimination System (NPDES) regulations require permitted facilities to monitor the quality of their wastewater discharge and report this data to the Environmental Protection Agency (EPA) or the state permitting authority on a Discharge Monitoring Report (DMR). Each state will have its own policies and procedures in place, including the frequency of monitoring and locations for monitoring.

At the very least, states must require:

• Annual monitoring for all pollutants in the NPDES permit (unless the permittee has been granted a waiver).
• Monitoring at the location where limits are calculated and applied.
• Results of all monitoring of permitted discharges conducted using approved methods to be sent to the permitting authority.

General permits

General permits are written to cover one or more categories (or subcategories) of discharges, disposal practices, or types of facilities in a geographic area, such as a state or a greater metro area.

Permits, including effluent limitations and a compliance schedule, apply to the following industry categories:

Applying for coverage under a NPDES general permit

EPA says that NPDES general permits do not require facility operators to “apply” for coverage. Instead, general permits typically rely on the submission of Notice of Intent (NOI) document.

The NOI is submitted after the general permit is issued by the permitting authority. It gives notice to the NPDES permitting authority of an operator’s intent to be covered under the general permit. The NOI usually contains information about the facility and the planned discharge for which coverage is needed. (Note: Some general permits automatically cover some discharges without submission of an NOI. EPA’s Pesticide General Permit is an example of this type of permit.)

Industrial Classification Codes: SIC and NAICS codes

Effective June 12, 2019, facilities must use both the North American Industry Classification System (NAICS) codes and the Standard Industrial Classification (SIC) codes that reflect the products or services provided by the facility when applying for a NPDES permit (or state permit).

Why SIC and NAICS?

EPA says both SIC codes and NAICS codes provide useful information. For example, SIC codes are referenced in several effluent limitations guidelines regulations that serve as the basis for effluent limitations in NPDES permits. While EPA may elect to replace those SIC codes with NAICS codes at some point in the future, the SIC code is currently a critical piece of information needed for NPDES permitting purposes.

However, NAICS codes are now the federal data standard typically used to identify and classify industrial operations. Although the NAICS codes are not directly linked to most Clean Water Act regulations, they are the recommended industry classification system used by the federal government. NAICS codes have effectively replaced SIC codes, which have not been updated since 1987. Use of the NAICS codes as the data standard across all federal data systems keeps things consistent across multiple federal databases.

Individual permits

• An NPDES individual permit is written to reflect site-specific conditions of a single discharger based on information submitted by in a permit application and is unique to that discharger.
• EPA has developed eight individual permit application forms that match up to the different categories of discharges subject to permitting.

A National Pollutant Discharge Elimination System (NPDES) individual permit is written to reflect site-specific conditions of a single discharger (or in rare instances to multiple co-permittees) based on information submitted by that discharger in a permit application and is unique to that discharger. Obtaining coverage under an individual permit may take more than six months.

Individual permits are specifically tailored to an individual facility. Once the facility has submitted the correct forms, the permitting agency will develop a permit for that facility based on information on the permit application and other information such as:

• Previous permits,
• Monitoring reports,
• Technology and water quality standards,
• Total maximum daily loads,
• Ambient water quality data, and
• Special studies.

The permitting authority then issues the permit to the facility for a specific period (five years or less). The facility must reapply before the expiration date.

The Environmental Protection Agency’s (EPA’s) regulations at 40 CFR 122.21 establish permit application requirements for applicants seeking coverage under individual permits. Further, EPA has developed eight individual permit application forms that match up to the different categories of discharges subject to permitting.

NPDES applications and program updates rule

In February 2019, EPA finalized new application requirements at 40 CFR 122.21 in the NPDES Applications and Program Updates Rule. The final rule, which became effective June 12, 2019, updated the eight forms applicants must use to apply for an individual NPDES permit.

States that run their own NPDES programs might use the new forms, or they may have developed their own NPDES application forms. However, those states must make sure their forms meet the program and regulatory changes in the new rule within one year (or up to two years if the state must make statutory changes).

NPDES Application Form 1: General Information. All applicants for individual NPDES permits (except publicly owned treatment works or other sewage treatment plants) must complete Form 1 and one or more of the following forms.

NPDES Application Form 2A: New and Existing Publicly Owned Treatment Works.

NPDES Application Form 2B: Concentrated Animal Feeding Operations and Concentrated Aquatic Animal Production Facilities.

NPDES Application Form 2C: Existing Manufacturing, Commercial, Mining, and Silvicultural Operations. This form is for facilities and operations that currently discharge process wastewater.

NPDES Application Form 2D: New Manufacturing, Commercial, Mining, and Silvicultural Operations. This is for those that have not yet commenced discharge of process wastewater.

NPDES Application Form 2E: Manufacturing, Commercial, Mining, and Silvicultural Facilities. This form is for those which discharge only non-process wastewater. This form is for new and existing facilities.

NPDES Application Form 2F: Stormwater Discharges Associated with Industrial Activity. This form is for new or existing facilities whose discharge is composed entirely of stormwater associated with industrial activity, excluding discharges from construction activity under 40 CFR 122.26(b)(14)(x) or (b)(15). If discharge is composed of stormwater and non-stormwater, complete Forms 1 and 2F, and Form 2C, 2D, or 2E, as appropriate.

NPDES Application Form 2S: New and Existing Treatment Works Treating Domestic Sewage.

Cooling water intake structures

• Permits for cooling water intake structures address the intake of water rather than the discharge of water into waters of the United States.

Cooling water intake structure means the total physical structure and any associated constructed waterways used to withdraw cooling water from waters of the U.S. The cooling water intake structure extends from the point at which water is first withdrawn from the waters of the U.S. source up to, and including, the intake pumps.

Unlike all the other industrial activities covered by the National Pollutant Discharge Elimination System (NPDES) wastewater permits, permits for cooling water intake structures address the intake of water rather than the discharge of water into waters of the United States. The Environmental Protection Agency (EPA) has established national performance standards designed to reduce the number of fish and other marine life killed by a facility’s cooling water intake structure into the cooling system.

40 CFR Parts 122 and 125 apply to cooling water intake structures at existing facilities. Effective October 14, 2014, the rules apply to existing facilities that use cooling water intake structures to withdraw water from waters of the United States and have or require an NPDES permit.

Existing facilities subject to this regulation include those with a design intake flow greater than 2 million gallons per day (mgd) and use at least 25 percent of the water they withdraw exclusively for cooling purposes. Facilities that require NPDES permits, but do not meet the two mgd intake flow threshold must check with their permitting authority to see if the rules apply to them.

Generally, facilities that meet these criteria fall into two major groups: steam electric generating facilities and manufacturing facilities.

The three main components of the rule are:

1. All affected facilities must reduce fish impingement. They may choose from one of seven options for meeting the best technology available requirements.
2. Existing facilities that withdraw at least 125 million gallons per day are required to conduct studies to help their permitting authority determine whether and what site-specific controls, if any, would be required to reduce entrainment. This decision process includes public input.
3. New units that add electrical generation capacity at an existing facility must also add technology that achieves one of two alternatives under national standards for entrainment for new units at existing facilities.

Pretreatment program

• Facilities that discharge to a POTW are known as indirect dischargers.
• The pretreatment program places much of the responsibility on local municipalities.

Another type of discharge that is regulated by the Clean Water Act (CWA) is one that goes to publicly owned treatment works (POTWs). The national pretreatment program (CWA 307(b)) controls the indirect discharge of pollutants to POTWs by “industrial users.” Facilities that discharge to a POTW are known as indirect dischargers.

The regulations establish responsibilities of government, industry, and the public to implement pretreatment standards to control pollutants from the industrial users which may pass through or interfere with POTW treatment processes or contaminate sewage sludge.

The Environmental Protection Agency (EPA) has developed technology-based standards for industrial users of POTWs. Different standards apply to existing and new sources within each category. EPA has also developed categorical pretreatment standards applicable to an industry on a nationwide basis. In addition, POTWs develop their own local limits, to assist in achieving the effluent limitations in their permits.

Regardless of whether a state is authorized to implement either the National Pollutant Discharge Elimination System (NPDES) or the pretreatment program, if it develops its own program, it may enforce requirements more stringent than federal standards.

Who’s the authority?

The pretreatment program places the majority of the responsibility on local municipalities. All large POTWs (i.e., those designed to treat flows of more than five million gallons per day) and smaller POTWs with significant industrial discharges establish local pretreatment programs.

These local programs enforce all national pretreatment standards and requirements in addition to any more stringent local requirements necessary to protect site-specific conditions at the POTW.

To ensure compliance with pretreatment requirements, POTWs:

• Identify and locate all industrial users (IUs) subject to the pretreatment program;
• Identify the character and volume of pollutants contributed by such users;
• Notify users of applicable pretreatment standards and requirements;
• Receive and analyze reports from IUs;
• Sample and analyze IU discharges and evaluate the need for IU slug control plans;
• Investigate instances of noncompliance; and
• Comply with public participation requirements.

Pretreatment defined

Pretreatment refers to the requirement that industrial sources discharging wastewater to POTWs control their discharges and meet limits on the amount of pollutants allowed to be discharged.

The control of the pollutants may necessitate treatment prior to discharge to the POTW (therefore, the term pretreatment).

Limits may be met by:

• Pollution prevention techniques (product substitution recycle and reuse of materials); or
• Treatment of wastewater.

Pretreatment program standards

• There are two sets of pretreatment program standards, categorical pretreatment standards and prohibited discharge standards.

There are two sets of pretreatment program standards:

1. Categorical pretreatment standards, and
2. Prohibited discharge standards.

These uniform national requirements restrict the level of pollutants that may be discharged by nondomestic sources to sanitary sewer systems.

Categorical pretreatment standards are limits on pollutant discharges to publicly owned treatment works (POTWs) that apply to specified process wastewaters of particular industrial categories. These are found in the regulations at 40 CFR 403.6 and 40 CFR Parts 405-471.

Prohibited discharge standards prohibit the discharge of wastes that pass through or interfere with POTW operations (including sludge management). These are the general prohibitions. There are also specific prohibitions that prohibit the discharge from all nondomestic sources, certain types of wastes that:

• Create a fire or explosion hazard in the collection system or treatment plant;
• Are corrosive, including any discharge with a pH less than 5.0, unless the POTW is specifically designed to handle such wastes;
• Are solid or viscous pollutants in amounts that will obstruct the flow in the collection system and treatment plant, resulting in interference with operations;
• Contain any pollutant discharged in quantities sufficient to interfere with POTW operations; and
• Have temperatures above 104°F when they reach the treatment plant or are hot enough to interfere with biological processes.

These standards are found in 40 CFR 403.5.

Local limits establish limits for pollutants (e.g. metals, cyanide, five-day biochemical oxygen demand, total suspended solids, oil and grease, organics) that may cause interference, pass through, sludge contamination, and/or worker health and safety problems if discharged in excess of the receiving treatment plant’s capabilities and/or receiving water quality standards.

If a facility qualifies as an industrial user, it’s the company’s responsibility to comply with applicable pretreatment standards and reporting requirements set by the local program. Demonstration of compliance requires certain users to submit reports, self-monitor, and maintain records.

Industrial activity and MSGP

• If the primary SIC code of the facility is one of those identified in the regulations, the facility is subject to the stormwater permit application requirements.
• Most states run their own NPDES stormwater permitting program through authorization from federal EPA.

The phrase “stormwater discharge associated with industrial activity” means a stormwater discharge from one of 11 categories of industrial activity defined at 40 CFR 122.26. Six of the categories are defined by Standard Industrial Classification (SIC) codes while the other five are identified through narrative descriptions of the regulated industrial activity.

If the primary SIC code of the facility is one of those identified in the regulations, the facility is subject to the stormwater permit application requirements. If any activity at a facility is covered by one of the five narrative categories, stormwater discharges from those areas where the activities occur are subject to stormwater discharge permit application requirements.

Those facilities/activities that are subject to stormwater discharge permit application requirements are:

• Category One (i): Facilities subject to federal stormwater effluent discharge standards at 40 CFR Parts 405-471
• Category Two (ii): Heavy manufacturing (e.g., paper mills, chemical plants, petroleum refineries, steel mills and foundries)
• Category Three (iii): Coal and mineral mining and oil and gas exploration and processing
• Category Four (iv): Hazardous waste treatment, storage, and disposal facilities
• Category Five (v): Landfills, land application sites, and open dumps with industrial wastes
• Category Six (vi): Metal scrapyards, salvage yards, automobile junkyards, and battery reclaimers
• Category Seven (vii): Steam electric power generating plants
• Category Eight (viii): Transportation facilities that have vehicle maintenance, equipment cleaning, or airport deicing operations
• Category Nine (ix): Treatment works treating domestic sewage with a design flow of one million gallons a day or more
• Category Ten (x): Construction sites that disturb five acres or more
• Category Eleven (xi): Light manufacturing (e.g., food processing, printing and publishing, electronic and other electrical equipment manufacturing, public warehousing and storage)

Note that Category Ten (x), construction sites that disturb five acres or more, are permitted separately through the National Pollutant Discharge Elimination System (NPDES) Stormwater Construction permit.

To determine whether a particular facility falls within one of these categories, consult the regulations at 40 CFR Part 122.

Multi-Sector General Permit (MSGP)

Most states run their own NPDES stormwater permitting program through authorization from the federal Environmental Protection Agency (EPA). Industrial facilities in those states will need to obtain NPDES permit coverage through the state.

EPA remains the permitting authority in a few states, most territories, and most tribal lands. For industrial facilities located in those areas, permit coverage is available under EPA’s 2015 Multi-Sector General Permit (MSGP).

Areas where EPA remains the NPDES permitting authority and has made the permit available for coverage include:

• Idaho, Massachusetts, New Hampshire, and New Mexico;
• The District of Columbia;
• U.S. territories except for the Virgin Islands;
• Federal facilities in Colorado, Delaware, Vermont, and Washington;
• Most Indian Country lands; and
• Other specifically designated activities in specific states (e.g., oil and gas activities in Texas and Oklahoma).

Construction stormwater permits

• Construction operators intending to seek coverage under the CGP must submit a NOI certifying that they have met the permit’s eligibility conditions and that they will comply with the effluent limits and other requirements.
• The NPDES stormwater program requires permits for discharges from construction activities that disturb one or more acres, and from smaller sites that are part of a larger common plan of development or sale.

Stormwater discharges from construction activities that disturb one or more acres, or smaller sites that are part of a larger common plan of development or sale, are also regulated under the National Pollutant Discharge Elimination System (NPDES) stormwater program. Before any stormwater can leave the site, construction operators must obtain coverage under a NPDES permit. This permit will either be administered by the state, or by the Environmental Protection Agency (EPA), depending upon where the site is located.

Where EPA is the permitting authority, construction stormwater discharges are almost always permitted under the Construction General Permit (CGP). The CGP requires compliance with effluent limits and other permit requirements, such as the development of a Stormwater Pollution Prevention Plan (SWPPP).

Notice of Intent (NOI)

Construction operators intending to seek coverage under the CGP must submit a Notice of Intent (NOI) certifying that they have met the permit’s eligibility conditions and that they will comply with the permit’s effluent limits and other requirements. Use EPA’s eNOI system to submit NOIs, or submit NOIs for the Multi-Sector General Permit, Pesticides General Permit, and Vessel General Permit at www.epa.gov/npdes/electronic-notice-intent-enoi.

Construction General Permit

Most states are authorized to implement the NPDES stormwater program for regulated construction stormwater discharges. EPA’s 2017 permits apply only in a handful of states where EPA remains the permitting authority. Many states have additional permitting requirements covering construction stormwater activities.

EPA 2017 CGP coverage is available for operators of eligible construction activities in the following areas:

• Idaho, Massachusetts, New Hampshire, New Mexico, District of Columbia;
• American Samoa, Guam, Johnston Atoll, Midway and Wake Islands, North Mariana Islands, Puerto Rico;
• Indian Country lands within Alaska, Arizona, California, Colorado, Connecticut, Idaho, Iowa, Kansas, Louisiana, Massachusetts, Michigan, Minnesota, Montana, Nebraska, Nevada, New Mexico, New York, North Dakota, Oklahoma, Oregon, Rhode Island, South Dakota, Texas, Utah, Vermont, Washington, Wisconsin, Wyoming;
• Areas within Colorado, Delaware, Vermont, Washington subject to construction by federal operators;
• Limited areas of Oklahoma and Texas.

2017 Construction General Permit

On January 11, 2017, EPA issued the 2017 stormwater Construction General Permit (CGP) under the NPDES. The new permit took effect at midnight on February 16, 2017.

Information for the CGP can be found online, including the permit itself, a fact sheet, and supporting information. See www.epa.gov/npdes/epas-2017-construction-general-permit-cgp-and-related-documents.

Modifications to the 2017 CGP

EPA issued final modifications to the CGP on May 28, 2019. The modified permit replaces several conditions in the original 2017 CGP and relevant fact sheet sections. All other permit conditions remain the same. In addition, the permit still expires on February 16, 2022.

Note: The modification does not affect permit coverage and no action is required of existing operators regarding the authorization to discharge under the CGP. If a facility is covered under the 2017 CGP, the facility will still be covered under the modified permit.

Note: The modification applies to the federal CGP only and does not affect state-issued permits.

Who needs a permit?

The NPDES stormwater program requires permits for discharges from construction activities that disturb one or more acres, and discharges from smaller sites that are part of a larger common plan of development or sale.

Construction stormwater permits include:

• Effluent limits for erosion and sediment control,
• Pollution prevention, and
• Site stabilization.

Municipal separate storm sewer system (MS4s)

• EPA rolled out the regulations for MS4s in two major phases.

Stormwater runoff that is contaminated by pollutants picked up on city streets, from residential gardening and yard care activities, and industrial sites is commonly transported through municipal separate storm sewer systems (MS4s). This polluted water may be discharged, untreated, into local water bodies.

An MS4 is a conveyance or system of conveyances that is:

• Owned by a state, city, town, village, or other public entity that discharges to waters of the U.S.,
• Designed or used to collect or convey stormwater (e.g., storm drains, pipes, ditches),
• Not a combined sewer, and
• Not part of a sewage treatment plant, or publicly owned treatment works (POTWs).

To prevent harmful pollutants from being washed or dumped into MS4s, operators may be required to obtain National Pollutant Discharge Elimination System (NPDES) permits and develop stormwater management programs (SWMPs). The SWMP describes the stormwater control practices that will be used to minimize the discharge of pollutants from the sewer system.

MS4s Phase I, Phase II

The Environmental Protection Agency (EPA) rolled out the regulations for MS4s in two major phases.

The 1990 Phase I regulation applies to medium and large cities or certain counties with populations of 100,000 or more. These highly populated areas had to obtain NPDES permit coverage for their stormwater discharges. There are approximately 855 Phase I MS4s covered by 250 individual permits.

The 1999 Phase II regulation required small MS4s (as defined by the U.S. Census Bureau) urbanized areas, and MS4s designated by the permitting authority, to obtain NPDES permit coverage for their stormwater discharges.

Phase II also includes non-traditional MS4s such as public universities, departments of transportation, hospitals, and prisons. Most of the 6,695 Phase II MS4s are covered by statewide general permits; however, some states use individual permits.

Sources of pollutants in stormwater runoff

• Stormwater runoff is water from rain or snowmelt that does not immediately soak into the ground and flows over or through natural or artificial storage or conveyance systems.
• EPA has identified six types of activities at industrial facilities that have the potential to be major sources of pollutants in stormwater.

Stormwater runoff is water from rain or snowmelt that does not immediately soak into the ground and flows over or through natural or artificial storage or conveyance systems. When undeveloped areas are converted to land uses with impervious surfaces such as buildings, parking lots, and roads, the natural hydrology of the land is altered and can result in increased surface runoff rates, volumes, and pollutant loads.

Stormwater runoff picks up industrial pollutants and typically discharges them directly into nearby waterbodies or indirectly via storm sewer systems. Runoff from areas where industrial activities occur can contain toxic pollutants (e.g., heavy metals and organic chemicals) and other pollutants such as trash, debris, and oil and grease, when facility practices allow exposure of industrial materials to stormwater. This increased flow and pollutant load can impair waterbodies, degrade biological habitats, pollute drinking water sources, and cause flooding and hydrologic changes to the receiving water, such as channel erosion.

Stormwater runoff can carry pollutants from impervious surfaces to receiving waters. Industrial facilities typically perform a portion of their activities in outdoor areas exposed to the elements. This may include activities such as material storage and handling, vehicle fueling and maintenance, shipping and receiving, and salt storage, all of which can result in pollutants being exposed to precipitation and capable of being carried off in stormwater runoff. Also, facilities may have performed industrial activities outdoors in the past and materials from those activities still remain exposed to precipitation. In addition, accidental spills and leaks, improper waste disposal, and illicit connections to storm sewers may also lead to exposure of pollutants to stormwater.

The Environmental Protection Agency (EPA) has identified six types of activities at industrial facilities that have the potential to be major sources of pollutants in stormwater:

1. Loading and unloading operations. Loading and unloading operations can include pumping of liquids or gases from tankers to storage facilities, pneumatic transfer of dry chemicals, transfer by mechanical conveyor systems, or transfer of bags, boxes, drums or other containers by forklift or other material handling equipment. Material spills or losses in these areas can accumulate and be washed away during a storm.
2. Outdoor storage. Outdoor storage activities include storage of fuels, raw materials, by-products, intermediate products, final products, and process residuals. Materials may be stored in containers, on platforms or pads, in bins, boxes or silos, or as piles. Storage areas that are exposed to rainfall and/or runoff can contribute pollutants to stormwater when solid materials wash off or materials dissolve into solution.
3. Outdoor process activities. Although many manufacturing activities are performed indoors, some activities, such as timber processing, rock crushing, and concrete mixing, occur outdoors. Outdoor processing activities can result in liquid spillage and losses of material solids, which makes associated pollutants available for discharge in runoff.
4. Dust or particulate generating processes. Dust or particulate generating processes include industrial activities with stack emissions or process dusts that settle on surfaces. Some industries, such as mines, cement manufacturing, and refractories, also generate significant levels of dust that can be mobilized in stormwater runoff.
5. Illicit connections and non-stormwater discharges. Illicit connections of process wastes or other pollutants to stormwater collection systems, instead of to sanitary sewers, can be a significant source of stormwater pollution. Non-stormwater discharges include any discharge from the facility that is not generated by rainfall runoff (for example, wash water from industrial processes). With few exceptions, these non-stormwater discharges are prohibited. Refer to the permit for a list of authorized non-stormwater discharges.
6. Waste management. Waste management practices include everything from landfills to waste piles to trash containment. All industrial facilities conduct some type of waste management at their site, much of it outdoors, which must be controlled to prevent pollutant discharges in stormwater.

What needs to be in a SWPPP?

• Facilities must prepare a SWPPP before submitting a NOI for permit coverage.
• The SWPPP must contain seven required elements.

The Stormwater Pollution Prevention Plan (SWPPP) is a site-specific, written document that:

• Identifies potential sources of stormwater pollution at the industrial facility;
• Describes stormwater control measures that are used to reduce or eliminate pollutants in stormwater discharges from the industrial facility; and
• Identifies procedures the operator will use to comply with the terms and conditions of the 2015 Multi-Sector General Permit (MSGP) or state general industrial stormwater permit.

A facility is required to develop the SWPPP to address the specific conditions at the site and keep it up to date to reflect changes at the facility’s site for the company’s use and for review by the regulatory agencies responsible for overseeing permit compliance.

Facilities must prepare a SWPPP before submitting a Notice of Intent (NOI) for permit coverage. If a facility prepared a SWPPP for coverage under a previous version of the National Pollutant Discharge Elimination System (NPDES) permit, they must review and update the SWPPP to implement all provisions of this permit prior to submitting the NOI. The SWPPP is intended to document the selection, design, and installation of control measures to meet the permit’s effluent limits. The SWPPP must contain all of the following elements:

• Stormwater pollution prevention team,
• Site description,
• Summary of potential pollutant sources,
• Description of control measures,
• Schedules and procedures,
• Documentation to support eligibility considerations under other federal laws, and
• Signature requirements.

Where an SWPPP refers to procedures in other facility documents, such as a Spill Prevention, Control, and Countermeasure (SPCC) Plan or an Environmental Management System (EMS), copies of the relevant portions of those documents must be kept with the SWPPP.

Caution: Owners and operators of industrial facilities subject to a state or Environmental Protection Agency (EPA) industrial stormwater general permit typically must develop a SWPPP as a basic requirement. If the facility is subject to such a requirement, failing to develop a SWPPP can result in enforcement action against the facility by EPA or the state. For example, EPA has targeted enforcement actions against some industrial sectors for failing to have developed SWPPPs for their facilities.