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Reducing Phosphorus Pollution

Phosphorus in Products Information


In the ongoing effort to improve water quality in Washington’s waters, the state is reducing one of the most common causes of pollution: phosphorus in household products.

In Washington State, at least 260 bodies of water are polluted because of nutrients like phosphorus. Phosphorus is a common ingredient in household detergents and fertilizers, where it is often described as “phosphate.” It is used in many industrial processes. Phosphorus also occurs naturally in soil and human and animal wastes.

Why it matters

In water, phosphorus behaves as a fertilizer, accelerating plant and algae growth. When plants and algae die, bacteria consume oxygen that is dissolved in the water. When this happens, less oxygen is available for fish and aquatic life that need oxygen to survive. Excess phosphorus is difficult to remove and requires more chemicals when treating drinking water, which adds cost.

Where phosphorus comes from

Industry and wastewater treatment plants account for about half of the phosphorus found in Washington waters. The other half comes from a variety of “nonpoint” sources. These sources are hard to trace with no obvious point of discharge, such as stormwater runoff, septic tanks, and agriculture.

Why reduce phosphorus use

We can greatly improve water quality by reducing our use of phosphorus-based products. The best way to protect our state’s water is to prevent phosphorus pollution in the first place.

Before 2010, automatic dishwasher detergent accounted for an estimated 10 to 12 percent of the phosphorus entering municipal wastewater plants. Treatment plants can remove much of the phosphorus in wastewater, but they cannot treat and remove all phosphorous. The phosphorus that treatment plants cannot remove is released into Washington’s waters in treated wastewater.


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Last updated June 2013











Sandy Howard,
Communications Mgr.
WA Dept. of Ecology
Phone: 360-407-6408

Brook Beeler
Education and Outreach
Eastern Regional Office
WA Dept. of Ecology
Phone: 509-329-3478