Water Supply Integration

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Starting in 2026, Hillsboro Water will supplement our water source from the Tualatin River with an additional source from the Willamette River. The Willamette Water Supply System (WWSS) is a collaboration between the City of Hillsboro, the Tualatin Valley Water District, and the City of Beaverton to bring an additional source of water to our community to meet future needs and challenges.

Hillsboro and our WWSS partners have been preparing for supply integration since 2018. This project has been presented to panels of national experts in drinking water quality and distribution systems to ensure we meet the following goals:

Maximize water quality compatibility between the Tualatin River and the Willamette River sources.

Prepare the water distribution systems for an additional water supply.

Prepare a comprehensive integration plan to best serve our community.

While most customers won’t notice a change in water service, this project prepares our community for the future.

Preparing for the Willamette

Hillsboro Water staff began preparing our distribution system for water supply integration in 2018. These efforts will facilitate the transition and ensure water remains safe to use and drink as the new system comes online.

Preparations include:

Researching other water supply integration projects.

Conducting special lab and field studies.

Modeling how our two water supplies will blend.

Increasing water quality monitoring.

Preparing the distribution system through flushing.

WWSS Water Treatment Process

Water will be treated at a state-of-the-art treatment facility using the latest technology to meet or exceed strict drinking water standards. Water will be monitored and tested 24 hours per day, 7 days per week. The plant will initially produce up to 60 million gallons of water per day (MGD) but will be designed for a maximum of 120 MGD.

Intake Facility

Fine screens prevent debris in the river from entering the treatment facility.

Sediment Removal

Removed silt and other contaminants.

Ozone Treatment

Kills microorganisms, prepares water for additional contaminant removal, and improves taste and odor.

Filtration

Granular activated carbon and sand filters remove cloudiness, organic material, and chemical contaminants.

UV Light Disinfection

Ultra-violet (UV) light kills remaining microorganisms.

Chlorine Disinfection

Protects treated water as it travels through miles of pipes to your water provider.

Delivery

Water will be delivered to Hillsboro in new, large-scale, earthquake-resilient pipes.

Contact Us

Thanks to our water treatment processes and rigorous water quality testing, most customers will not notice a difference in their water service. Minor aesthetic changes could occur during the integration process, like a difference in taste or smell, but these changes are temporary and pose no health risks.

If you have any questions or concerns about your water service, our Water Quality team is here to help.

503-615-6702