Keep phosphorus out of our lakes!

Why is phosphorus bad for lakes?

Phosphorus is a nutrient that stimulates plant growth - that's why it's in most fertilizers. In a lake, excess phosphorus encourages algae growth. Too much algae causes scum to form on the lake's surface and harms water quality. As algae dies and decays, it looks and smells bad. As it breaks down, it also uses up oxygen in the water that fish and other wildlife need.

How does phosphorus get into lakes?

Stormwater and groundwater carry phosphorus into the lake from a number of sources, including:

• fertilizers from gardens and small farms
  
• detergents
  
• failing septic tanks
  
• pet and livestock waste
  
• soil - naturally phosphorus-rich in this area - that erodes during landscaping and development
  

So, even though we may not know it, each of us puts phosphorus into the lake - often by the things we do every day in our own backyards. Whether we live right on the lakeshore or upstream in the basin, we all contribute to the problem and we need to work together to solve it.

How can I keep phosphorus out of lakes?

Fertilize your lawn and garden sparingly -

Fertilize once or twice a year at most. Use compost or organic fertilizers; they last longer and pollute less. Don't apply fertilizer when rain is in the weather forecast.

Plant native plants

They need less water, fertilizer and other chemicals.

Maintain your septic tank

Have it professionally checked every two or three years and serviced as needed.

Scoop your pet waste and dispose of it properly

Even small amounts of waste can pollute. Also, if you own livestock, consider fencing to keep them and their waste out of lakes and streams.

Avoid washing your car on the street

Instead, wash it on the lawn where natural filtering will keep soap out of the lake. Better yet, take it to a commercial car wash, where wastewater is treated and recycled.

Where can I find out more?

For information on organic alternatives to phosphorus fertilizers, call the Washington Toxics Coalition at 632-1545 (ask for the lawn care flyer) or Seattle Tilth's Green Gardening Program at 547-7561. For information on maintaining your septic tank, call the Seattle - King County Department of Public Health at 296-4932.