Stormwater Management

What is Stormwater?

Stormwater is the result of precipitation from rain, snowmelt, and other weather events that eventually makes its way into our surface waters, including the water we drink.  As it flows across impervious surfaces such as roads, sidewalks, parking lots, and driveways, stormwater runoff eventually makes its way into the Village’s stormwater system.

Since the inlets to the stormwater system are located all around the Village, stormwater runoff can sometimes pick up substances such as:

  • Fertilizers, pesticides, and lawn chemicals
  • Gasoline, Oil and other hydrocarbons
  • Trash and debris
  • Sediment from construction sites
  • Micro-organisms and bacteria

What is an MS4?

The acronym MS4 stands for Municipal Separate Storm Sewer System. This system is made up of ditches, curbs, gutters, storm sewers, and similar means of collecting or conveying runoff collected from impervious surfaces. The Village of Upper Brookville’s MS4 is subject to the EPA’s regulations for Phase II Small MS4s and is permitted through the New York State Department of Environmental Conservation (NYSDEC). The Village is responsible for the maintenance of the MS4 as well as ensuring that all development taking place within the Village complies with NYSDEC regulations. The MS4 does not connect with a wastewater collection system or treatment plant eventually, the stormwater is discharged directly into surface waters, which include streams, ponds, reservoirs, Oyster Bay Harbor and Long Island Sound.

The National Pollutant Discharge Elimination System (NPDES) Stormwater Program regulates stormwater discharges from three potential sources: municipal separate storm sewer systems (MS4s), construction activities, and industrial activities.  A federal regulation, commonly known as Stormwater Phase II, requires permits for stormwater discharges from Municipal Separate Storm Sewer Systems (MS4s) in urbanized areas and for construction activities. To implement the law, the New York State Department of Environmental Conservation has issued two general permits, one for MS4s in urbanized areas and one for construction activities.

Under Phase II, operators of regulated small municipal separate storm sewer systems (MS4s) are required to develop and implement a stormwater management program which includes the six minimum control measures:

1, Public Education & Outreach
2. Public Participation/Involvement
3. Illicit Discharge Detection & Elimination
4. Construction Site Run-off Control
5. Post Construction Run-off
6. Pollution Prevention/Good Housekeeping

Each MS4 municipality is also required to submit a stormwater management plan and an annual stormwater report. Below is Upper Brookville’s latest stormwater plan and report prepared by West Side Engineering, PC:

Upper Brookville Stormwater Management Program Annual Report Year 20 – March 10, 2022 to March 9, 2023

If you have any questions or comments regarding the report, please email Tracy Lynch – Clerk/Treasurer, at