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Earth Environmental Education What Is Nonpoint Source Pollution?

What is nonpoint source pollution?


Drawing by Rex, Ava Elementary School

Nonpoint source (NPS) pollution comes from so many sources that one point cannot be identified.

Rainfall or melting snow flows over and into the ground. It picks up and carries away both natural and human-made pollutants. 

These pollutants end up in lakes, rivers, wetlands, and even our underground sources of drinking water. 


What causes nonpoint source pollution? 

We all play a part. Nonpoint source pollution comes from a wide variety of human activities on the land. Each of us can contribute to the problem without even realizing it. 

Nonpoint source pollutants include:

  • Excess fertilizers, herbicides, and insecticides from farms, homes and towns 

  • Oil, grease, and toxic chemicals from cars and the roads and parking lots they use

  • Sediment and erosion from construction sites, pasture and crop lands, and eroding streambanks 

  • Salt from irrigated land 

  • Acid drainage from abandoned mines 

  • Bacteria and nutrients from livestock, pet wastes, and faulty septic systems
  • What are the effects of these pollutants on our waters?

    Nonpoint source pollution is the leading remaining cause of water quality problems. The effects of nonpoint source pollution are hard to measure. However, we know that these pollutants have harmful effects on drinking water supplies, recreation, fisheries, and wildlife.

     What can we do about nonpoint source pollution?