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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

Eliminating fats, oils and grease from our sewers

Just as grease clogs your arteries, it clogs the local sewer district's and County's arteries--the sewer system.

Don't pour grease down the sink! Grease down the drain leads to... Grease in sewer

Grease going down the drain can cause serious problems in our sewers...
and in your house drains and side sewer.

What are disposal options?

Item Disposal method
Fats, oil and grease  Residents may dispose fats, oil and grease in their garbage can. You should mix large amounts of liquid fat, oil or grease with an absorbent material, such as cat litter or sawdust, so it doesn't leak while it's being transported for disposal. For more information, please visit "What do I do with" (King County Solid Waste Division) and select Fats, Oil and Grease
Used cooking oil
Turn used cooking oil into Biodiesel! Rather than dumping used cooking oil down the kitchen sink, which can lead to costly visits by the plumber, residents now have a new, free recycling resource at their fingertips – a public cooking oil drop off depot where every gallon collected will be transformed into low carbon biodiesel. 

General Biodiesel, Inc.
(external link)
6333 1st Ave. S,
Seattle, WA, 98108
206-932-1600

Additional residential used cooking oil drop-off locations:

List of drop off locations for used cooking oil.
View map
 (13 locations in King County, external link).

Where does grease come from?

Greasy bacon in a fry panFats, oils and greases are a byproduct of cooking. They are found in such things as:

  • Meat fats
  • cooking oil
  • Lard and shortening
  • butter and margarine

When grease is washed down the drain, it sticks to the inside of sewer pipes (both on your property and in the streets.) Over time, it builds up and can block an entire pipe.

Garbage disposals do not keep grease out of the pipes, they only shred it into smaller pieces. Commercial additives, including detergents that claim to dissolve grease, may pass it down the line and cause problems away from the source.

The results of a grease-blocked sewer pipe can be:

  • Sewage overflows in your home or your neighbor's home
  • Expensive and unpleasant cleanup that often must be paid for by the property owner. The average cleanup cost is about $3,000 which does not include replacing carpets and repairing walls.
  • Possible contact with disease-causing organisms
  • An increase in operation and maintenance costs by the local sewer district and King County's regional treatment system, which causes higher sewer bills for customers.

Thanks for doing your part to keep fats, oils and greases out of the sewer

The links at the right have more information and disposal tips.

News releases

"One of the best ways people can keep fats and grease out of the sewer is to keep it out of their drains. Not only does it help prevent sewer system overflows, it can help people avoid their own costly plumbing problems."

-- Christie True, Director, Department of Natural Resources and Parks

Additional information available on the Web

External links