In 1972, Congress enacted the Clean Water Act (CWA). Under the CWA, discharge of pollutants to waters of the United States from any point source is unlawful unless the discharge is covered under a National Pollutant Discharge Elimination System (NPDES) permit. Regulated point sources include stormwater discharges from municipal separate storm sewer systems (MS4s). Phase I of the NPDES permitting program, issued in 1990, requires medium and large cities or certain counties with populations of 100,000 or more to obtain NPDES permit coverage for their stormwater discharges. Phase II, issued in 1999, requires regulated small MS4s in urbanized areas, as well as small MS4s outside the urbanized areas that are designated by the permitting authority, to obtain NPDES permit coverage for their stormwater discharges.

The New York State Department of Environmental Conservation (NYSDEC) administers a state program which has been approved by the United States Environmental Protection Agency for the control of wastewater and stormwater discharges in accordance with the CWA. Under New York State law the program is known as the State Pollutant Discharge Elimination System (SPDES) and regulates stormwater discharges to waters of the state, which includes state designated freshwater and tidal wetlands as well as surface waters.

On March 20, 2009, the Town received official notice from the NYSDEC that it had been formally designated as a municipal separate storm sewer system operator that would be required to obtain coverage under the NYSDEC SPDES General Permit for Stormwater Discharges from Municipal Separate Storm Sewer Systems (MS4s), Permit No. GP-0-08-002. The NYSDEC authorized the Town to discharge stormwater under this permit on September 29, 2009, after receiving a completed Notice of Intent (NOI). The general permit was subsequently modified and re-issued as GP-0-15-003, which authorizes stormwater discharges from the Town's regulated MS4s until April 30, 2017.

As a SPDES permitted entity, the Town must “Develop, implement, and enforce a Stormwater Management Program Plan (SWMPP) designed to reduce the discharge of pollutants from the MS4 to the Maximum Extent Practicable (MEP) in order to protect water quality and to satisfy the requirements of the Clean Water Act.”