To explore the feasibility of regional I/I control, the King County Regional Infiltration and Inflow (I/I) Control Program was created in 1999 as part of the Regional Wastewater Services Plan (RWSP).
|1999||Program created as part of the Regional Wastewater Services Plan (RWSP).|
|2000||Comprehensive 6-year, $41 million I/I control study began, led by WTD staff working in a consensus-based approach with local sewer agencies.|
|2001–2002||Current levels of I/I defined for each local agency tributary to the regional system through extensive flow monitoring and modeling programs.|
|2003–2004||10 pilot projects in 12 local agency jurisdictions selected and constructed to demonstrate the effectiveness of collection system rehabilitation projects, test technologies, and gain cost information.|
|2004||Final draft model standards, procedures, policies, and guidelines developed for use by local agencies to reduce I/I in their systems.|
|2005||Thorough benefit-cost analysis completed to determine the cost-effectiveness of I/I reduction and Executive recommends a regional I/I control program.|
Long-term regional I/I control plan developed and then approved by the King County Council.
WTD and local sewer agencies conducted an I/I reduction feasibility analysis and selected three initial I/I reduction project areas.
Initial I/I reduction project in the Skyway Water & Sewer District service area (unincorporated King County) constructed. I/I reduction projects in Bellevue and Issaquah were cancelled in early 2010 due to County budget limitations.
|2014||Findings on the initial project published, which will be used to develop recommendations to the King County Council regarding long-term I/I reduction controls.|
|2015 – 2018||Conducting regional planning work to evaluate programmatic concepts to reduce I/I particularly in private side sewers. This planning effort is in progress, and has resulted in several technical memorandum.|