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Wastewater Treatment

King County, Washington

For questions about the Wastewater Treatment Division website, please send an e-mail message or contact us at:

King Street Center
201 S. Jackson St., Suite 500
Seattle, WA 98104-3855
Phone: 206-477-5371
Fax: 206-684-1741
Telecommunication device for the deaf (TTY): 711

Get Directions to our office location in Seattle, Washington.

Staff Contacts

Only 1 percent of water on earth is fresh and available

Support use of reclaimed water in place of fresh water


Support use of reclaimed water in place of fresh water

Reclaimed water comes from wastewater that has been cleaned to the Washington Departments' of Ecology and Health Class A standards and can be used for just about anything except drinking. Instead of sending this resource to Puget Sound, recycled water can replace fresh water for landscaping and agricultural irrigation, industrial processing, and city uses such as street sweeping. Reclaimed water is available even during dry summer months or when a drought strains other water resources.

So, what's with all these different types of water?

We know it can be confusing so here are some definitions to make things easier.

Fresh water: Fresh water is naturally occurring, has almost no salt, and is used by every land animal for drinking. Fresh water exists on the surface in lakes, rivers, streams, and wetlands but it also exists in large underground aquifers. Sometimes the fresh water found in aquifers is also called groundwater.

Drinking water: Before freshwater comes into our homes, it goes through a drinking water treatment plant for cleaning. Through the Safe Drinking Water Act, the EPA sets standards for drinking water and protects fresh water and ground water resources from pollution and contamination. This water is also called potable water.

Grey water: is water that has been used in sinks, showers, and washing machines. This water is not clean but is still usable on plants, gardens, and lawns.

Reclaimed water: is wastewater that has been cleaned to the Departments' of Ecology and Health Class A standards and can be used for just about anything except drinking.

Stormwater: is rain water that falls on streets, yards, buildings and runs off in storm drains. Most of this water goes untreated to the Puget Sound. Some mixes into the sewer pipes and goes to treatment plants.

Did you know: The type of water that is in your toilet, outdoor hoses, and fire hydrants is drinking water? What would be a better type of water for those uses? 

Helpful hint: Any purple pipes or purple fire hydrants you see are reclaimed water infrastructure.

Find out how you can help save water!
Use less water

Rain catchment systems: support low impact development.

Collect rain water to irrigate during summer.
Collect water to irrigate