What are nutrients?


  • Are essential elements that living organisms need to live, grow, and reproduce (e.g. Phosphorus)

  • Are naturally occurring in our surrounding environment in very small amounts

  • Can be harmful to plants, animals, and water quality when introduced to the environment in excessive quantities.


  • Is a naturally occurring nutrient found in water, soil, and air

  • Stimulates plant growth and is an essential nutrient for both animals and plants to be able to live, grow, and reproduce

  • Promotes natural levels of plant growth when found in naturally balanced amounts in the environment

  • Can lead some species, such as algae, to experience explosive growth when exposed to excessive amounts of phosphorus

Why should I care?

Explosive growth of algae can create large algal blooms that cloud the water and block out the sunlight for other plants and aquatic life, which can kill them or limit their growth. When algae die, they sink to the bottom of the lake and begin to decompose. Bacteria feed on this decomposing algae and consume the oxygen in the water. This process can deplete dissolved oxygen levels in the lake to a level that is too low to support other plant and animal life.

In 1998, Lake Whatcom was listed as a polluted waterbody because it failed to meet state dissolved oxygen standards due to high amounts of phosphorus entering the Lake. These resulting water quality problems triggered a Total Maximum Daily Load (TMDL) study by the Washington Department of Ecology.

How does phosphorus enter our lakes and streams?

While phosphorus is a naturally occurring nutrient, other phosphorus sources from our homes and neighborhoods may include:

  • Phosphorus-containing soaps, detergents, and chemicals

  • Phosphorus-containing fertilizers

  • Pesticides

  • Exposed soil from construction and landscaping

  • Animal waste

  • Failing septic tanks

  • Car washing

  • Leaves and grass clippings

These phosphorus sources are carried into our lakes and streams in runoff from rainfall or outdoor water use. As water runs off hard surfaces, like driveways, roads, and patios, it picks up phosphorus-containing pollutants and carries them into our streams or into storm drains which empty directly into our waterways.

What can I do to help?

  • Use phosphorus-free soaps, detergents, and chemicals

  • Use phosphorus-free fertilizers

  • Pick up after your pets!

  • Wash your car at a commercial carwash or on your lawn