Nutrient Pollution


Nutrient pollution is caused by an excess of nutrients, primarily nitrogen and phosphorus, in water. While nitrogen and phosphorus are important components of a healthy ecosystem, there can be “too much of a good thing”.  An overabundance of nutrients in rivers and lakes can lead to an overgrowth of algae.  An overabundance in groundwater can lead to high nitrate levels in wells which can cause ‘blue baby syndrome’.  When water with excess nutrients is disinfected with chlorine to make drinking water, the nutrients and chlorine react to form disinfection byproducts, some of which increase the risk of cancer.

Harmful Algal Blooms (HABs)lake_algae_t440

Nutrient pollution can lead to algal blooms that can harm food resources and habitats.  They decrease the oxygen in water that is necessary for aquatic life to survive, which can lead to fish kills and aquatic dead zones.  Some algal blooms  produce toxins that cause illness in people and animals who touch or drink the water or who eat tainted fish or shellfish.

Click here for algae-related advisories for boaters and swimmers in Indiana lakes.

Click here for information from the Indiana State Department of Health on health effects and to report an algae-related illness


There are many causes of nutrient pollution, most of which are human induced.

  • Agriculture – runoff of fertilizer and manure and soil erosion
  • Stormwater – runoff of leaves, grass clippings and other debris from roads, sidewalks, and rooftops
  • Wastewater – sewer and septic systems
  • Homeowners – yard fertilizers, pet waste, yard waste, detergents and soaps that contain nitrogen and phosphorus


An EPA report from 2015 details the many economic losses caused by nutrient pollution including the costs of

  • Drinking water treatment
  • Clean up of polluted water bodies
  • Tourism and recreation losses
  • Commercial fishing and shellfish losses
  • Declines in waterfront property values
  • Health expenses


What You Can Do At Home:

  • Choose cleaning supplies that are phosphate free.
  • Dispose of pet waste properly
  • Maintain septic systems
  • Clear leaves and debris from storm drains so they don’t wash into waterways
  • Wash vehicles in proper locations (for example, at designated car washes, where the waste water is handled appropriately)
  • Learn more and take the ‘Clear Choices, Clean Water’ pledge at:

What You Can Do In Your Yard:

  • Lawn Care:
    • Reduce or eliminate fertilizer use
    • Do not apply fertilizer close to rivers or streams
    • Do not over water lawns and gardens
    • Properly store and dispose of unused fertilizers and containers
  • Garden Care:
    • Plant a rain garden with native, water-loving plants that help prevent erosion and runoff
    • Install a rain barrel
    • Use pervious pavers for walkways and driveways to allow water to soak into the ground rather than runoff
    • Install a green roof
    • Use yard waste in mulch and compost rather than letting it wash into waterways

What You Can Do In Your Community: