Water Infrastructure

The complex business of getting clean water to your home includes a hidden water system that consists of 1,800 miles of pipes, 17,000 valves, and 191,000 water meters.

Infrastructure. It may sound boring, but take a deeper look. You'll find the amazing role Seattle Public Utilities' pipes, pumps and treatment plants play to bring some of the best water in the world to your tap.

  • It starts with the watersheds, over 100,000 protected acres, that provide some of the cleanest water. We're the envy of the nation, with such a safe and reliable source of mountain water. These watersheds also provide habitat for our salmon and other animals and plants.
  • Water travels to two treatment plants that treat and test the water to ensure it is safe. Because of the purity of the source water, we don't need to do as much treatment as other cities that have less pure source water.
  • It travels through 1,800 miles of water mains.
  • It is monitored 24 hours a day, seven days a week, by people responding to breaks, power outages, pumping station issues and coordinating with street and electricity construction projects.
  • It is stored in covered reservoirs in the city, protected from contamination.
  • It's there, tasty, clean and safe, when you turn on the tap.

It takes hundreds of people, and lots of equipment, to bring you what you have come to expect: the best water in the nation, for less than a penny a gallon.

Photo of Amy LaBarge in front of the Cedar River in winter.
Amy LaBarge, Division Director for Watershed Management Division: "I like the fact that SPU owns and maintains both of its watersheds. It makes me proud that we have control of the quality of our water from our watersheds to your faucet."


Photo of the Landsburg Diversion Dam
Landsburg Diversion Dam, first built in 1901


Water treatment

The water beneath our feet is necessary for life, yet few of us think about the amazing system that delivers it to our taps. Water treatment alone is a complex endeavor: Cedar River water is disinfected with ozone, ultraviolet light, and chlorine. South Fork Tolt water, which is slightly different, is ozonated, filtered, and disinfected with chlorine. Both supplies have minerals added for corrosion control. Then, our water is ready to drink.

Photo of the Tolt water treatment facility
The interior of the Tolt water treatment facility

Public Utilities

Andrew Lee, General Manager and CEO
Address: 700 5th Avenue, Suite 4900, Seattle, WA, 98104
Mailing Address: PO Box 34018, Seattle, WA, 98124-5177
Phone: (206) 684-3000

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Seattle Public Utilities (SPU) is comprised of three major direct-service providing utilities: the Water Utility, the Drainage and Wastewater Utility, and the Solid Waste Utility.