EPA: NPDES Small MS4 Urbanized Area Clarification
SUMMARY: The U.S. Environmental Protection Agency (EPA) is finalizing clarifications to its National Pollutant Discharge Elimination System (NPDES) Stormwater Phase II regulations due to recent changes made by the Census Bureau. The changes to EPA's regulations are limited to clarifying that the designation criteria for small municipal separate storm sewer systems (MS4s), which have been used since the promulgation of the regulations in 1999, will remain the same. These clarifications are necessary due to the Census Bureau's recent decision to discontinue its practice of publishing the location of “urbanized areas” along with the 2020 Census and future censuses. The clarifications in this final rule replace the term “urbanized area” in the Phase II regulations with the phrase “urban areas with a population of at least 50,000,” which is the Census Bureau's longstanding definition of the term urbanized areas. This change allows NPDES permitting authorities to use 2020 Census and future Census data in a manner that is consistent with existing longstanding regulatory practice.
DATES: This final rule is effective on July 12, 2023, published in the Federal Register June 12, 2023, page 37994.
View final rule.
§122.28 General permits (applicable to State NPDES programs, see §123.25). | ||
(a)(1)(vi) | Revised | View text |
§122.32 As an operator of a small MS4, am I regulated under the NPDES storm water program? | ||
(a)(1) | Revised | View text |
(d) introductory text | Revised | View text |
§122.33 Requirements for obtaining permit coverage for regulated small MS4s. | ||
(b)(3) | Revised | View text |
§123.35 As the NPDES Permitting Authority for regulated small MS4s, what is my role? | ||
(b)(1)(ii) | Revised | View text |
(b)(2) | Revised | View text |
(d)(1) | Revised | View text |
Previous Text
§122.28 General permits (applicable to State NPDES programs, see §123.25).
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(a)(1)(vi) Urbanized areas as designated by the Bureau of the Census according to criteria in 30 FR 15202 (May 1, 1974); or
§122.32 As an operator of a small MS4, am I regulated under the NPDES storm water program?
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(a)(1) Your small MS4 is located in an urbanized area as determined by the latest Decennial Census by the Bureau of the Census. (If your small MS4 is not located entirely within an urbanized area, only the portion that is within the urbanized area is regulated); or
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(d) The NPDES permitting authority may waive permit coverage if your MS4 serves a population of less than 1,000 within the urbanized area and you meet the following criteria:
§122.33 Requirements for obtaining permit coverage for regulated small MS4s.
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(b)(3) Co-permittee alternative. If the regulated small MS4 is in the same urbanized area as a medium or large MS4 with an NPDES storm water permit and that other MS4 is willing to have the small MS4 operator participate in its storm water program, the parties may jointly seek a modification of the other MS4 permit to include the small MS4 operator as a limited co-permittee. As a limited co-permittee, the small MS4 operator will be responsible for compliance with the permit's conditions applicable to its jurisdiction. If the small MS4 operator chooses this option it must comply with the permit application requirements of §122.26, rather than the requirements of §122.33(b)(2)(i). The small MS4 operator does not need to comply with the specific application requirements of §122.26(d)(1)(iii) and (iv) and (d)(2)(iii) (discharge characterization). The small MS4 operator may satisfy the requirements in §122.26 (d)(1)(v) and (d)(2)(iv) (identification of a management program) by referring to the other MS4's storm water management program.
§123.35 As the NPDES Permitting Authority for regulated small MS4s, what is my role?
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(b)(1)(ii) Guidance: For determining other significant water quality impacts, EPA recommends a balanced consideration of the following designation criteria on a watershed or other local basis: discharge to sensitive waters, high growth or growth potential, high population density, contiguity to an urbanized area, significant contributor of pollutants to waters of the United States, and ineffective protection of water quality by other programs;
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(b)(2) Apply such criteria, at a minimum, to any small MS4 located outside of an urbanized area serving a jurisdiction with a population density of at least 1,000 people per square mile and a population of at least 10,000;
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(d)(1) You may waive permit coverage for each small MS4s in jurisdictions with a population under 1,000 within the urbanized area where all of the following criteria have been met: