Stormwater Rules and Notices-Final Rules
Congress gives EPA authority to develop and implement federal stormwater regulations. Any new or modified regulations must go through a rulemaking process. The process includes a proposal, public comment, and a final rule that must then be implemented and enforced.
EPA also publishes a variety of notices associated with the stormwater program, including draft and final stormwater permits, technical corrections to stormwater permits, and notices on stormwater regulations. Here is more information on the laws, regulations, proposed and final rules, and other public notices applicable to the NPDES stormwater program.
- Final Rule Clarifies Phase II Regulations Related to Census Bureau Changes - EPA issued this final rule to clarify that new small MS4 designations will be based on whether the previously unregulated MS4s are located in urban areas with a population of 50,000 or more people. The clarification was necessary because the designation criteria in the Phase II regulations had previously been based on the location of “urbanized areas” (defined as urban areas with a population of 50,000 or more people), and the Census Bureau announced in March 2022 (pdf) (286.6 KB) that it would no longer provide mapping information on such urbanized areas.
- Final MS4 Updates to NPDES Electronic Reporting Rule (April 15, 2020) (PDF) (13 pp, 354 K About PDF) - EPA has finalized updates to specific data elements within the NPDES Electronic Reporting Rule (PDF) (96 pp, 1 MB, About PDF) that apply to regulated MS4s. These changes are necessary to reflect the changes made to the Phase II stormwater rule by the promulgation of the MS4 General Permit Remand Rule (PDF) (33 pp, 367 K, About PDF).
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Final MS4 General Permit Remand Rule (December 9, 2016) - EPA has finalized modifications to the Phase II stormwater regulations relating to the use of general permits for small MS4s in response to a Ninth Circuit remand of these regulations. The final rule establishes two alternative approaches an NPDES permitting authority can use to issue and administer small MS4 general permits that address the court remand.
- Mark-Up Version of MS4 General Permit Remand Rule
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MS4 Permits - Compendium of Clear, Specific and Measurable Permitting Examples - Includes current provisions expressed in “clear, specific, and measurable” terms
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Amendments to the NPDES Regulations for Stormwater Discharges Associated with Oil and Gas Exploration, Production, Processing, or Treatment Operations or Transmission Facilities (June 12, 2006) – Consistent with the Energy Policy Act of 2005, this final rule exempts construction activities at oil and gas sites from the requirement to obtain an NPDES permit for stormwater discharges except in very limited instances. EPA issued a public notice for the proposed rule which opened on January 6, 2006 and closed on February 21, 2006. The rule became effective June 12, 2006.
Note: This rule was vacated effective November 2008. The effective requirements are the regulations in place prior to the 2006 rule plus the additional Energy Policy Act clarification of the activities included in the CWA 402(l)(2) exemption.
- National Pollutant Discharge Elimination System - Regulations for Revision of the Water Pollution Control Program Addressing Stormwater Discharges; Final Rule (December 08, 1999) – Phase II regulations expanded the existing NPDES stormwater program (Phase I) by addressing stormwater discharges from small MS4s and construction sites that disturb one-five acres. Although those sources are automatically designated by the rule, the rule allows for the exclusion of certain sources from the national program based on a demonstration of the lack of impact on water quality, and the inclusion of others based on a higher likelihood of localized adverse impact on water quality. The regulations also exclude from the NPDES program stormwater discharges from industrial facilities that have "no exposure" of industrial activities or materials to stormwater.
- National Pollutant Discharge Elimination System Permit Application Regulations for Stormwater Discharges; Final Rule (November 16, 1990) – Phase I established regulations setting forth NPDES permit application requirements for stormwater discharges associated with industrial activity; discharges from a municipal separate storm sewer system serving a population of 250,000 or more; and discharges from municipal separate storm sewer systems serving a population of 100,000 or more, but less than 250,000.