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Regional Wastewater Services Plan (RWSP)

Since the King County Council adoption of the Regional Wastewater Services Plan (RWSP) in 1999, the Conveyance System Improvement (CSI) program has focused on implementing RWSP conveyance policies.

The Conveyance System Improvement program works to:

  • Use the 20-year peak flow storm as the design standard for its separated wastewater system to avoid sanitary sewer overflows
  • Ensure sufficient capacity in the regional conveyance system to accommodate planned growth
  • Include future population growth when sizing facilities

The 1999 RWSP called for approximately 20 CSI projects to address capacity needs in the regional wastewater conveyance system through 2030. The 20 projects were spread amongst three components:

  • Conveyance needed to serve the Brightwater Treatment Plant
  • Major conveyance improvements
  • Improvements to minor pipelines (“trunks”) in the system

CSI program updates

Since the initial adoption of the Regional Wastewater Services Plan (RWSP) in 1999, the CSI program has been updated in 2004, 2007, and 2017.

Conveyance System Improvement

For more information, please contact:

Steve Tolzman
steve.tolzman@kingcounty.gov
 206-477-5459

Steve Tolzman
Capital Project Manager

206-477-5459