As stormwater flows over the land, it can pick-up pollutants. Common pollutants in urban systems include:

  • Bacteria - from pet and wildlife waste, and failing septic systems
  • Phosphorous - from tree leaves, grass clippings, soil erosion, fertilizer, and pet and wildlife waste
  • Sediment - from exposed soil on construction sites, sparse lawns, and unprotected garden beds set close to hard surfaces like streets, sidewalks, and driveways
  • Chloride - from road salt
  • Trash

Unlike the water that goes into a drain inside your home, stormwater does not get routed to a treatment plant to get cleaned. Instead, stormwater is routed directly to local lakes, ponds, wetlands, and creeks. Learn hoe you can do your part to protect our water.

Stormwater can also cause cause flooding and drainage issues when the stormwater management network is overwhelmed. Sometimes parks and streets are used to temporarily hold water during and after a storm in order to protect downstream structures and waterbodies. If you're unsure whether standing water is planned of if there is a problem, contact the Engineering Department.

What is Runoff?

When vegetation is limited and water is left to pass through drain pipes instead of being filtered out naturally, runoff occurs. In suburban areas, runoff often passes through naturally vegetated areas, which slows down the velocity of the water and in turn filters pollutants and sediments. In urban areas, storm water is frequently passed through storm pipe drains instead of vegetation due to the fact that the vegetation is typically more limited and has likely already been altered by the storm water and its pollutants.

Because urban runoff does not originate from a distinct "point" source (e.g. an industrial discharge pipe), it is often referred to as a "non point source pollution". These pollutants in urban runoff could negatively impact the vitality of our municipality on many levels and are not always visible to the naked eye.

Urban runoff can do the following damage to our community:

  • Alter the physical, chemical, and biological characteristics of water bodies to the detriment of aquatic and terrestrial organisms
  • Make beaches and rivers unsightly for unsafe for human contact
  • Negatively impact beneficial activities and users, including water recreation, commercial fishing, tourism, and aquatic habitats

To receive email notifications about Combined Sewer Overflows (CSO) in New Haven, visit the link here.