Why do I need coverage under the Small Municipal Separate Storm Sewer System (MS4) General Permit?

This permit is for certain public entities that operate municipal separate storm sewer systems (MS4s). The permit authorizes the discharge of stormwater to protected surface waters from Small MS4s, which may include:

  • A city, town or county located fully or partially within an urbanized area as determined by the latest Decennial Census by the Bureau of Census
  • State, federal and other publicly-owned properties that discharge stormwater
  • Other areas designated by ADEQ.

The permit requires the development of a stormwater management program. The permittees are required to follow six minimum control measures that must be built into their program including:

  • Public Education and Outreach
  • Public Involvement and Participation
  • Illicit Discharge Detection and Elimination (IDDE) Program
  • Construction Site Stormwater Runoff Control
  • Post-Construction Stormwater Management
  • Pollution Prevention and Good Housekeeping.

Coverage under the general permit is valid during the five-year term of the permit. Permittees must pay an annual fee.

The 2021 general permit is effective as of Sept. 30, 2021, and replaces the 2016 general permit. The 2021 general permit includes protections for non-WOTUS protected surface waters, incorporating Arizona’s new Surface Water Protection Program (SWPP)1 | Visit SWPP Page >

The 2021 general permit was appealed. Based on the appeal agreements, ADEQ modified the permit in September 2022 as follows:

Permit | View/Download >
Fact Sheet | View/Download >
Response to Comments | View/Download > 

Submit a Notice of Intent (NOI), Annual Report and Discharge Monitoring Report (DMR)

To obtain an NOI and submit an annual report or DMR, you will need to use myDEQ, ADEQ's online portal. Get an account or log in to myDEQ at your convenience 24/7 | Register Today > | Log In to myDEQ >