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Water Infrastructure

Our hidden water system — 1,800 miles of pipes, 20,000 valves, 188,000 water meters.

The complex business of getting clean water to your home

  • Tony BlackwellTony Blackwell, Division Director for Water Transmission and Distribution
    "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."
  • Landsburg Diversion Dam, first built in 1901.
  • Tolt water treatment facility.

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 plants that treat and test the water to ensure it is safe. Because of the purity of the source water, we do much less treatment than other cities.
  • It travels through 1,800 miles of water mains. We schedule regular preventative maintenance to prevent leaks and breaks.
  • 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 658 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.

A world of water below

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.