Most of the member communities are subject to the requirements of United States Environmental Protection Agency’s (USEPA’s) 2016 National Pollutant Discharge Elimination System (NPDES) Small Municipal Separate Storm Sewer System (MS4) Permit for Massachusetts, also known as the 2016 Massachsuetts Small MS4 General Permit.

Regulation under the MS4 Permit is required when the residential population of a municipality (including adjacent densely settled surrounding area) exceeds 50,000, and the municipality has an overall population density that exceeds 1,000 people per square mile. By these definitions, the area subject to the requirements of the MS4 Permit may be just a portion of a municipality, a boundary referred to as the Urbanized Area. This page includes links to the 2016 Massachusetts MS4 Permit, as well as guidance documents on stormwater policy from the USEPA and the Massachusetts Department of Environmental Protection (DEP).

Each of the regulated communities is required, in the 2016 MS4 Permit, to submit an annual report that describes actions it completed in the reporting year to meet its stormwater objectives. Reports submitted since 2003 are available on the USEPA website. The report for the first year of the Permit was due in 2004, and is shown as ‘04’, the report for the second year is ‘05’, and so on.  Annual reports for all MS4 regulated communities can be viewed by clicking on the left.