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Nonpoint Source Pollution


Nonpoint source pollution is water pollution that originates from many different sources. It differs from point source pollution, which occurs when pollutants are discharged into a body of water at a single, known location, such as from a wastewater treatment plant or an industry. Nonpoint source pollution is caused by precipitation events that pick up and carry away natural and human-made pollutants, depositing them into lakes, rivers, wetlands, coastal waters, and even our underground sources of drinking water. Pollutants in water include a wide spectrum of chemicals and/or pathogens, including the following:

  • Excess fertilizers, herbicides, and insecticides from agricultural lands and residential areas;
  • Oil, grease, and toxic chemicals from urban runoff and energy production;
  • Sediment from improperly managed construction sites, crop and forest lands, and eroding streambanks;
  • Bacteria and nutrients from livestock, pet wastes, and faulty septic systems;
  • Excess nutrients, such as phosphorus and nitrogen, which can cause algae blooms.

According to the U.S. Environmental Protection Agency (EPA), nonpoint source pollution is the leading cause of water pollution in the United States today. Individuals can play an important role by practicing conservation and by changing certain everyday habits. Here are a few recommendations:

  • Keep litter, pet wastes, leaves, and debris out of street gutters and storm drains. These outlets drain directly to lake, streams, rivers, and wetlands.
  • Apply lawn and garden chemicals sparingly and according to directions. 
  • Dispose of used oil, antifreeze, paints, and other household chemicals properly, not in storm sewers or drains. 
  • Control soil erosion on your property by planting ground cover and stabilizing erosion-prone areas. 
  • Wash your car on your lawn, rather than in your driveway, to prevent runoff.