Stormwater Pollution

According to the EPA, stormwater is one of the largest pollution sources faced by many of our lakes, rivers and streams.


One of the main culprits of water pollution in the watershed is stormwater runoff.

When rain falls on hard surfaces, it washes bacteria and parasites from pet waste; and chemicals from fertilizer, pesticides, herbicides, ice melt, motor oil, antifreeze, and windshield washer fluid directly into catch basins or storm drains.

Storm drains are connected via underground pipes to nearby water bodies, and all of the contaminated runoff flows directly into local streams, rivers, ponds, and the ocean, untreated.

Polluted stormwater causes problems for local drinking water sources; recreational activities like swimming, boating and fishing; and aquatic life.

The simplest way to prevent stormwater pollution is to keep our pavement clean and redirect water away from storm drains.

Click here to learn how to prevent polluted stormwater runoff on your property.

NepRWA Helps Communities thru the Neponset Stormwater Partnership

On July 1, 2018, the Environmental Protection Agency finalized a tough new stormwater permit for local municipalities.

We plan to help our communities with their stormwater cleanup efforts through regional cooperation and resource sharing, under the umbrella of the Neponset Stormwater Partnership (NSP).

The partnership communities are cooperating on creating key permit documents, printing regional public outreach materials, creating model stormwater bylaws, and figuring out the best way to pay for it all. The goal is more effective cleanup at a lower cost, through economies of scale.

Partners include the towns of Canton, Dedham, Foxborough, Medfield, Milton, Norwood, Quincy, Sharon, Stoughton, and Westwood, along with the Metropolitan Area Planning Council (MAPC), and the Neponset River Watershed Association.

Learn more about the Neponset Stormwater Partnership:

Protecting receiving waters

Before the landscape was developed, far more rainwater would seep into the ground and be filtered by soil, plant roots and microorganisms, before joining the groundwater or seeping from the soil into a waterway.

Today, realizing just how much of the ground has been covered in impervious material, communities are incorporating stormwater-cleaning structures, called BMPs (Best Management Practices) into the built landscape.  Examples of BMPs include bioretention cells, rain gardens and tree-filter-boxes.

Best Management Practices (BMPs) either can be structural or non-structural.

Non-structural BMPs are implemented to change individual behaviors.Examples of non-structural BMPs include:

  • implemented changes to regulations and by-laws
  • installation of pet waste stations and/or catchbasin decals
  • implementation of improved street sweeping

Newly installed rain garden at Xaverian Brothers High School in Westwood.

Structural BMPs are physically built to treat stormwater before it reaches local waters. They are designed to receive water, treat it, and then discharge it to receiving waters. Examples of structural stormwater BMPs are:

  • bioretention cells
  • rain gardens
  • pocket wetlands

Over the last couple of years, the Watershed Association has worked with several towns to site structural BMPs and implement non-structural BMPs in an effort to minimize the effects of stormwater pollution in the Neponset River Watershed.

Click here for more information about stormwater BMPs.

Learn more about these programs from Environmental Scientist, Chris Hirsch, at 781-575-0354 x302 or

Click here for information on preventing residential stormwater pollution.