Wastewater Treatment Plant Expansion


What's New

Updated June 14, 2017 -
Major expansion of Pierce County’s Chambers Creek Regional Wastewater Treatment Plant is complete. Improvements increase sewer capacity, repair and replace aging infrastructure.


About the project

Work is substantially complete on a $342 million project to increase capacity and environmental benefit at the Chambers Creek Regional Wastewater Treatment Plant. The Pierce County Planning and Public Works Department’s expansion of the Chambers Creek Regional Wastewater Treatment Plant supports the future growth and economic development of Pierce County. The project increases capacity, improves treatment, preserves equipment and prepares the plant to comply with future National Pollutant Discharge Elimination (NPDES) permit requirements. 

Benefits include:

  • Increased sewer capacity
  • Repair and replace aging infrastructure 
  • New technologies that help protect the environment 

Why upgrade the plant?

We were reaching maximum capacity limits and treating 20 million gallons per day (MGD) of wastewater. The project is designed to increase the rated capacity by 15 MGD from 28.7 MGD to 44 MGD. County-owned infrastructure, such as the CCRWWTP, is vitally important to future economic growth and the avoidance of moratoriums on that growth. The upgraded facilities are designed to meet county population and economic growth through 2030 and prepare for projected growth through 2040 – with future improvements. 

Project timeline

Earth moving to prepare the site started in 2010. Facility construction began in 2013 with an anticipated completion in the Fall of 2016. Actual substantial completion is May 2017.


Project Location

Project Timeline

Project Photos

DEMON (Anammox)
Pilot Study


Project Funding

Total Project Cost:
Final cost for the project is approximately $342 million. This cost represents an $11 million savings from the project estimate of $353 million. 

Project Funding Sources:

  • $511,000 grant received from Washington State Department of Ecology (WSDOE) in March of 2011. This grant is from the ‘Clean Up Toxic Sites – Puget Sound’ fund and was approved by the State in the 2010 Supplemental Capital Budget Proviso Section 3010.
  • $60,000,000  loan received from WSDOE in August of 2014. This loan was funded by the Washington State Water Pollution Control Revolving Fund, 2014 funding cycle.
  • $196,090,000 sewer revenue bonds received in 2012.
  • $53,660,000 sewer improvement bonds received in 2010.
  • Sewer rate revenue.
  • Capacity charge revenue.

Design Engineer:

Brown & Caldwell 

General Contractor/Construction Manager:

 Mortenson Construction