East of Hudson Municipal Separate Storm Sewer System - NYC DEP

Environmental Protection


Programs for Communities & Businesses

East of Hudson Municipal Separate Storm Sewer System


Our East of Hudson (EOH) Watershed has a Municipal Separate Storm Sewer System (MS4) regulated by the New York State Department of Environmental Conservation (DEC). As a regulated MS4, the EOH Watershed is required to comply with the Phase II Stormwater Management Plan. For information about the New York City MS4 program, visit New York City Municipal Separate Storm Sewer System.

EOH Watershed MS4 Reports

The Phase II Stormwater regulations require the EOH Watershed to implement programs and practices to control stormwater runoff that may be polluted. Download the 2024 East of Hudson Watershed MS4 Notice of Intent.

East of Hudson MS4 Draft 2024-2025 Interim/Annual Report

The East of Hudson MS4 Draft 2024-2025 Interim/Annual Report is open for public comment. The 30-day public comment period is from February 8, 2025, through midnight on March 10, 2025. Please send comments to: ms4info@dep.nyc.gov.

Download the East of Hudson MS4 NYCDEP Draft Interim/Annual Report 2024-2025 (open for public comment until 3/10/25)

East of Hudson Watershed MS4 Interim Report

Download the 2024 East of Hudson Watershed MS4 Interim Report

For reports from previous years, please visit our Document Portal and search for “East of Hudson Watershed.”

Stormwater in the NYC Watershed

Stormwater from rain or melting snow can pick up and move sediment and a variety of pollutants. For information about stormwater programs, visit Stormwater Management in the New York City Watershed.

Understanding the Phosphorus Issue

In the EOH Watershed, the main pollutant of concern is phosphorus. To learn more about phosphorus, visit Understanding the Phosphorus Issue.

Pollution Prevention Best Practices

Because stormwater transports whatever is left on our lawns and roads, individual actions make a difference in determining the kinds and amounts of pollution.

Download the Homebuyer’s Guide to Septic Systems

Download the Homeowner’s Guide to Septic System Best Practices

Download the Putnam County Septic System Inspection Form

Download the Stormwater and Proper Construction Designs

You can learn more about pollution prevention practices by visiting the DEC website.

If you observe illegal dumping or discharges into any storm sewers, please call (914) 232-8642 or (845) 334-7185, or email ms4info@dep.nyc.gov.

Visit Stormwater Management and Sewer System for additional information and educational resources.

Safe Disposal of Harmful Products

Learn how to properly dispose of products that can clog our sewer system or harm our environment.

Resources for Educators

Use our maps, virtual tours, education modules and more to learn about New York City’s Environment.

Stormwater Management in the Watershed

New York City Watershed Regulations require stringent management of stormwater.

Understanding the Phosphorus Issue

One way to ensure good water quality is to limit the amount of phosphorus in stormwater runoff.