Rensselaer County Stormwater Management Program

What is stormwater?

Stormwater is water from rain or melting snow that does not soak into the ground. It flows from rooftops, over paved areas, bare soil, and sloped lawns. As it flows, stormwater runoff collects and transports soil, animal waste, salt, pesticides, fertilizers, oil and grease, debris and other potential pollutants.

What’s the problem?

Rain and snowmelt wash pollutants from streets, construction sites, and land into storm sewers and ditches. Eventually, the storm sewers and ditches empty the polluted stormwater directly into streams and rivers with no treatment. This is known as stormwater pollution.

Polluted stormwater degrades our lakes, rivers, wetlands and other waterways. Nutrients such as phosphorus and nitrogen can cause the overgrowth of algae resulting in oxygen depletion in waterways. Toxic substances from motor vehicles, and careless application of pesticides and fertilizers threaten water quality and can kill fish and other aquatic life. Bacteria from animal wastes and improper connections to storm sewer systems can make lakes and waterways unsafe for wading, swimming and fish consumption. Eroded soil is a pollutant as well. It clouds the waterway and interferes with the habitat of fish and plant life.

A sanitary sewer system and a storm sewer system are not the same.

Water that goes down a sink or other inside drain flows to either a wastewater treatment plant or to a septic system for treatment. Storm sewer flows are not treated. Water that flows down driveways, streets, and outside areas and into a storm sewer or ditch flows directly to the nearest creek, fish and wildlife habitats, downstream recreational areas, and drinking water supplies.

There are many types of pollutants that find their way into storm drains.

Some common pollutants found in storm sewers and creeks include:

  • Motor oil
  • Yard clippings
  • Fertilizers and pesticides
  • Soapy car wash water
  • Sediment eroded from construction projects
  • Litter
  • Animal waste

It’s important to remember that any type of surface water runoff, not just rainfall, can run into the storm sewer and collect in the stormwater management system. For example, when you wash your car on the driveway, that water ends up in the system. That’s why we need to be careful with what we put into the storm sewers as traces of all this material can end up in the stormwater system and our local waterways.

What is being done?

The Rensselaer County MS4 Communities is a forum for the regulated communities to share resources and work in partnership toward compliance with the United States Environmental Protection Agency (U.S. EPA) Phase II Stormwater requirements. The overall goal of the Communities is to utilize regional collaboration to identify existing resources and develop programs to reduce the negative impacts of stormwater pollution and ultimately improve the water quality on our streams and lakes.

The U.S. EPA Phase II Rule requires operators of small municipal separate storm sewer systems (MS4s) to develop and implement a stormwater management program that addresses six minimum controls.  For each of these six control measures, measurable goals are to be selected, management practices identified and implemented to achieve those measurable goals.

The term “MS4 communities” include states, counties, cities, towns, villages, school districts and any other quasi-governmental agency, such as special districts, that may have storm sewers that discharge into the environment.  Storm sewers include ditches, enclosed storm sewer systems, and storm drains and catch basins that have exit pipes.

The following are MS4 communities in Rensselaer County:

  • New York State
  • City of Rensselaer
  • City of Troy
  • Town of Brunswick
  • Town of East Greenbush
  • Town of Nassau
  • Town of North Greenbush
  • Town of Poestenkill
  • Town of Sand Lake
  • Town of Schaghticoke
  • Town of Schodack
  • Village of Castleton
  • Hudson Valley Community College


(1)         The Town of Nassau has received a waiver for the 2003 SPDES permit.

(2)         Significant portions of the cities of Rensselaer and Troy presently have combined sewer systems.

The EPA Phase II MS4 six minimum controls are listed below:

  1. Public Education & Outreach
  2. Public Participation and Involvement
  3. Illicit Discharge Detection and Elimination
  4. Construction Site Run-Off and Control
  5. Post Construction Site Run-Off and Control
  6. Pollution Prevention and Good Housekeeping for Municipal Operations

For information on the Rensselaer County MS4 Communities and how they are working to address the requirements of the EPA Phase II Stormwater Rule, contact the Rensselaer County Department of Economic Development and Planning at (518) 270-2914.

New York State Department of Environmental Conservation Links

Stormwater Information

SPDES Municipal Stormwater (MS4) Information

SPDES Construction Stormwater Information

SPDES Multi Sector General Permit

Municipal Pollution Prevention and Good Housekeeping Guidance

National Pollutant Discharge Elimination System (NPDES)

United State Environmental Protection Agency Links:

Stormwater Rules and Notices

The National Menu of Best Management Practices for Stormwater

Watershed Academy

Office of Water

Other Links of Interest

National Association of Home Builders Research Center

Managing Stormwater With Low Impact Development (LID) Practices

The Center for Watershed Protection

Strategies for watershed protection that encompasses watershed planning, watershed restoration, stormwater management, watershed research, better site design, education and outreach, and watershed training.

Rensselaer County MS4

Urbanized Area Boundary Map

(Click on Map)

Rensselaer County Hydrology Map

(Click on Map)

Public Participation & Involvement

Annual Reports:















Notice of Public Comment Period – 2021


Draft Erosion, Sediment Control and Stormwater Management Local Law

Draft IDDE Law

Draft Municipal Pollution Prevention Guidelines

MS4 Program and Municipal Departments