News List

Press Enter to show all options, press Tab go to next option

Hillsboro's Reliable Water Source & Our Water Future

Post Date:07/10/2018 8:58 am

Every drop of water that runs through Hillsboro Water customers’ taps is from a “surface water source,” meaning it comes out of a river or reservoir. 

Upper-Tualatin River at Lee Falls 

Hillsboro’s winter water source is the upper-Tualatin River. The Tualatin River’s main stem is roughly 80 miles in length and flows generally from west to east. The river starts in the Tillamook State Forest in Washington County and finally discharges into the Willamette River near West Linn, Oregon. The Tualatin River has been Hillsboro’s only winter water source for more  than 77 years.

In the summer, the Tualatin River level drops too low for community use, so Hillsboro customers rely upon water stored in the Barney and Scoggins Reservoirs to meet demand. The Barney Reservoir is located in the Trask River Watershed at 1,640 feet above sea level and holds 20,000 acre-feet of water at capacity. An acre-foot is the amount that covers an acre with a foot of water. The Scoggins Reservoir, also known as Hagg Lake, covers 1,132 acres and stores approximately 59,950 acre-feet of water when full.

Investing in Our Water Future
The City of Hillsboro and the Tualatin Valley Water District are partnering to develop the mid-Willamette River at Wilsonville as an additional water supply source. The upper-Tualatin River will continue to be Hillsboro’s primary water source, but in the next 25 to 50 years, the City anticipates the demand for approximately twice the amount of water currently available. 

Willamette River 

This additional water source will offer City of Hillsboro customers significant benefits, including excellent finished water quality, redundancy, ownership and control of the supply, year-round reliability, and better value.

Design and construction of the new Willamette Water Supply Program (WWSP) water delivery system is underway, and includes building:

  • A modified water intake on the Willamette River at Wilsonville.
  • A state-of-the-art water filtration facility in Tualatin/Sherwood.
  • Water supply tanks in Beaverton.
  • More than 30 miles of large-diameter transmission water pipeline traveling north from Wilsonville, through Beaverton, and into Hillsboro.

The WWSP has divided this major water infrastructure project into 10 smaller projects, to be built separately over several years, to allow business and contracting opportunities that benefit the local economy, provide jobs, and support regional economic development.

The entire WWSP system is being built to modern seismic standards and designed to withstand the impacts of a large earthquake or other natural disaster so that service can be quickly restored after a catastrophic event.

When complete and put into operation in 2026, the system will supply water to more than 350,000 Washington County residents and some of the state’s largest employers for the next 100 years. For additional information, call 503-941-4570 or visit

Return to full list >>