Where Your Water Comes From

Almost all water used in Clark County comes from underground aquifers which are tapped by a series of wells. In contrast, Portland gets most of its supply from above-ground sources, such as the Bull Run reservoir. Most of Clark Public Utilities’ wells are located in the Salmon Creek watershed. The average depth of our wells is 250 feet.

Four aquifers are the source of water:

  1. Recent Alluvial Aquifer
  2. Troutdale Aquifer
  3. Sand and Gravel Aquifer
  4. Fractured basalt formations

Here is a cross-section of the hydro-geologic structures in Clark County. For more information, call 360-992-8022.

The Curtis Well Field Project

In August, 2010, the Carol J Curtis Well Field was completed. The project is designed to become a major source of water for our customer-owners. It currently adds 7.2 million gallons of water per day to our pumping capacity. The first phase of the project included two deep wells, a water treatment facility and about one mile of 30-inch transmission line to connect the new supply source to the utility’s existing water system.

An extensive project to upgrade our water distribution facilities is underway. Some of our water lines are more than 50 years old, and are undersized. The funding for much of this work is coming from Washington’s low-interest Public Works Trust Fund.

Our Commitment to Quality

No fluoride or other chemicals, other than the required level of chlorination, are added to the water supply. The quality of the water is excellent — and we test it regularly to make sure it stays that way.

Most of the utility’s water wells are in the Salmon Creek watershed. 

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Additonal Water Services

In addition to providing your water service, our staff can:

  • Provide technical assistance on water quality testing with local laboratories contact information
  • Provide information on home water treatment units, backflow protection devices and many other water-related items
  • Offer advice and suggestions for finding leaks in your water system
  • Give tips to help you deal with high- and low-pressure water problems
  • Provide a list of certified Backflow Testers


  • The average annual use per residential customer is 80,000 gallons.
  • Clark Public Utilities has 35 wells which have a pumping capacity of 35 million gallons of water per day.
  • Water is stored in 33 reservoirs with a combined storage capacity of 18.9 million gallons.
  • We have about 883 miles of distribution lines.
  • The utility also manages 23 independent water systems throughout the county.

Join the Stream Team

Our water utility supports one of the strongest environmental restoration and enhancement efforts in the state. We sponsor and participate in many projects throughout the year to restore streams, enhance fish populations and educate children and adults alike about habitat and watershed stewardship.

Become a Stream Steward