Small Municipal Separate Storm Sewer Systems(MS4)

General Information


Human activities have impacted the environment by the creation of impervious surfaces and dispersal of residual pollutants. These changes have impacted surface waterbodies such as lakes, rivers and streams, through increased pollutant loads and changes to natural hydrologic patterns.  Nationwide EPA studies have identified runoff directly related to stormwater as a major contributor to water quality degradation.    

The objective of the Stormwater Management Plan (SWMP) is to develop stormwater pollution mitigation for the Town of Greenwich, Connecticut based on the guidelines established under the MS4 stormwater management program, the U.S. Environmental Protection Agency’s (EPA) National Pollutant Discharge Elimination System (NPDES) Stormwater Phase II Rule. This MS4 program was created with the intention of improving the nation’s waterways by reducing pollutant discharges to surface water bodies from stormwater.

The Connecticut Department of Energy & Environmental Protection (CTDEEP) locally regulates enforcement of the EPA program through its General Permit for the Discharge of Stormwater from Small MS4s (Permit).The Department of Public Works – Engineering Division has received a Small MS4s Permit. Below are copies of the Stormwater Management Plan and Annual Reports submitted to CTDEEP.

2017 MS4 General Permit (PDF)

2017 MS4 Annual Report (PDF)

2018 MS4 Annual Report (PDF)


2019 MS4 Annual Report (PDF  


2020 MS4 Annual Report (PDF)


2021 MS4 Annual Report (PDF)


2022 MS4 Annual Report  (PDF)