JWC Water Treatment Plant Expansion Project

Increasing Water Capacity, Strengthening Water Infrastructure & Ensuring Clean, Reliable Drinking Water for Customers

In response to the need to provide additional water for growing communities in western Washington County, the Joint Water Commission (JWC) —owned in partnership by the Cities of Hillsboro, Beaverton, Forest Grove and the Tualatin Valley Water District — are working to complete a multi-year water treatment expansion, improvements project, and facility plan for the JWC Water Treatment Plant.

The project, a result of nearly four years of water supply planning, addresses long-term water capacity and strengthens seismic resiliency while bringing the capacity of the plant from 75- to 85-million gallons (of water) per day (mgd) by 2019.

In addition to new and enhanced water treatment capabilities increasing the plant’s treatment capacity and reliability, the project also involves strengthening water infrastructure and planning for a future plant capacity of 105-mgd. A facility plan has been developed to lay the groundwork for the immediate plant expansion as well as phased seismic improvements and expansions until ultimate plant build out.

The JWC currently treats, transmits and stores drinking water for more than 365,000 customers, and is the largest conventional water treatment plant in Oregon.

For additional information on how the project will help provide safe and cost-effective drinking water to the water service partners for current and future needs, contact City of Hillsboro Project Manager Erika Murphy at 503-615-6720 or by e-mail.

Project Details

  • Project Status: Currently under construction
  • Completion: Summer 2019
  • Total Project Value: $35 million
  • Delivery Method: CM/GC
  • Project Manager: Erika Murphy, City of Hillsboro
  • Contractors: Jacobs (formerly CH2M) and Slayden Constructors

May 2018 Updates

  • May 2018 - JWC WTP Expansion Project36” diameter surge basin overflow piping installation has begun. Surge basin overflow piping is designed to prevent backflow through filters and flooding of the filter gallery.  
  • 24” diameter solids drying bed decant piping installation has begun. Decant piping recovers water used in the solids handling process and returns it back to the start of the treatment process.
  • Surge basin structure was filled with water and prepared for a water leak test. Multiple-day water leak tests demonstrate the ability of the structure to hold water and identify small cracks that require repair and sealing.
  • Filter structure foundation preparation, suspended slab formwork, and electrical conduit rough-in is ongoing.
  • Filter structure suspended concrete slabs poured.
  • Specialized 48“ diameter earthquake resistant ductile iron pipe (ERDIP) was installed at the filter effluent connection point. ERDIP pipe is designed to resist damage from ground movement during an earthquake.

Additional Resources

  • Joint Water Commission Water Treatment Plant Expansion to 85 MGD – Package 2 – GMP Submittal: The GMP is available for review at the partner agencies: Cities of HillsboroForest GroveBeaverton and the Tualatin Valley Water District (TVWD). For questions, contact Tacy Steele at 503-615-6732.