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Storage or disposal of water and fluids may be managed by injecting them underground using injection wells. Injection wells are regulated by the Underground Injection Control (UIC) program to protect underground sources of drinking water.
To operate an injection well, operators must receive approval through the UIC program. Some operators receive approval by submitting information that describes the operation such as well class, location, operating status, and operator contact information to the UIC program. Other operators need approval through a permit that identifies specific operating conditions in order to inject. All wells must be operated according to applicable UIC requirements.
Activities performed by the UIC program include maintaining well inventory, permitting injection wells, performing inspections, and ensuring compliance with permit requirements. When operators manage wells in a way that does not meet the applicable UIC requirements, the program alerts operators to issues and may assist operators in returning the wells to compliance or take enforcement action.
The UIC program may be implemented by the federal EPA or by states, territories, or tribes with EPA-approved primary permitting and enforcement authority. EPA has delegated primacy for all well classes to several states and territories.
Scope
The Safe Drinking Water Act of 1974 and its subsequent amendments established the UIC program, which protects underground source of drinking water (USDW) 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; or
- Conduct any other injection activity that endangers USDWs.
- 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.
Regulatory citations
- 40 CFR 124 — Procedures for decisionmaking
- 40 CFR 144 — Underground injection control program
- 40 CFR 145 — State UIC program requirements
- 40 CFR 146 — Underground injection control program: Criteria and standards
- 40 CFR 147 — State, tribal, and EPA-administered underground injection control programs
- 40 CFR 148 — Hazardous waste injection restrictions
Key definitions
- Approved State Program: A UIC program administered by the State or Indian Tribe that has been approved by EPA according to SDWA sections 1422 and/or 1425.
- Class: See 40 CFR 144.6 for the classification of injection wells.
- Draft permit: A document prepared under 124.6 indicating the Director’s tentative decision to issue or deny, modify, revoke and reissue, terminate, or reissue a “permit.” A notice of intent to terminate a permit, and a notice of intent to deny a permit, as discussed in 124.5 are types of “draft permits.” A denial of a request for modification, revocation and reissuance, or termination, as discussed in 124.5 is not a “draft permit.”
- Permit: An authorization, license, or equivalent control document issued by EPA or an approved State to implement the requirements of 40 CFR 144, 145, 146, and 124. “Permit” includes an area permit (144.33) and an emergency permit (144.34). Permit does not include UIC authorization by rule (144.21), or any permit which has not yet been the subject of final agency action, such as a “draft permit.”
- UIC: The Underground Injection Control program under Part C of the Safe Drinking Water Act, including an “approved State program.”
- Underground injection: A “well injection.”
- Underground source of drinking water (USDW): An aquifer or its portion: (a)(1) Which supplies any public water system; or (2) Which contains a sufficient quantity of ground water to supply a public water system; and (i) Currently supplies drinking water for human consumption; or (ii) Contains fewer than 10,000 mg/l total dissolved solids; and (b) Which is not an exempted aquifer.
- USDW: Underground source of drinking water.
- Well: A bored, drilled, or driven shaft whose depth is greater than the largest surface dimension; or, a dug hole whose depth is greater than the largest surface dimension; or, an improved sinkhole; or, a subsurface fluid distribution system.
- Well injection: The subsurface emplacement of fluids through a well.
Summary of requirements
EPA’s regulations group injection wells into six groups or “classes.” Classes I - IV and VI include wells with similar functions, construction, and operating features. This allows consistent technical requirements to be applied to these well classes. Class V wells are those that do not meet the description of any other well class. Wells in Class V do not necessarily have similar functions, construction, or operating features. The well classes are:
- Class I industrial and municipal waste disposal wells
- Class II oil and gas related injection wells
- Class III solution mining wells
- Class IV shallow hazardous and radioactive waste injection wells
- Class V wells that inject non-hazardous fluids into or above underground sources of drinking water
- Class VI geologic sequestration wells (for carbon dioxide)
- Get approval from your implementing agency to operate your injection well.
- Operate your well according to applicable UIC requirements.
- Submit permit applications,
- Monitor their wells and report the results, and
- Submit plugging and abandonment reports when they close their wells.
Class VI well operators are required to submit compliance data directly to EPA in an electronic format approved by EPA. This requirement applies regardless of whether the project is located in a state with primary enforcement responsibility (primacy) for Class VI wells. The Geologic Sequestration Data Tool (GSDT) is EPA’s centralized, web-based system that received, stores, and manages Class VI data to fulfill this requirement.