Regional Infiltration and Inflow Control Program

Initial I/I reduction projects

In accordance with the adopted I/I Control Program, King County will work with the local sewer agencies to:

Conduct an I/I reduction feasibility analysis in 2007-08 in four candidate project areas.
Select and implement 2-3 initial I/I reduction projects in 2010-12 to test the cost-effectiveness of I/I reduction on a scale large enough to potentially offset the need for larger conveyance or storage facilities.
Analyze the results of these initial projects and make recommendations to the King County Council regarding long-term I/I reduction and control, including applicable changes to policy or code.

Project schedule

Click on schedule to enlarge.

Next steps

During 2010-2012 King County will construct I/I reduction projects in up to three areas, selected from four candidate project areas shown on the map. Details about these projects will be determined during the pre-design and design phases in 2008-2009. Work being done during this time includes Sewer System Evaluation Survey (SSES) sewer inspections, I/I project cost estimating, cost-effectiveness analyses, and field work such as site condition assessments, geotechnical and environmental evaluations, and constructability reviews.

While some of the sewer rehabilitation work on selected projects will focus on the public portions of the sewer system (sewer mains and manholes), much of the rehabilitation work will happen on private side sewers and will require the cooperation of private property owners. King County and the local sewer agencies will work closely with the affected communities during the design and implementation of the projects.

To minimize the amount of excavation in neighborhoods, King County will use less invasive trenchless rehabilitation techniques whenever possible. Further information about the Initial I/I Reduction Projects, including final project selection recommendations, will be available on this website in the Predesign Report, due to be completed by November 2008.

More information

For questions about the I/I Control Program or the Initial I/I Reduction Projects, please contact Maryann Petrocelli at 206-263-7321 or maryann.petrocelli@kingcounty.gov .
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For questions about the I/I Control Program Web site, please contact Maryann Petrocelli at 206-263-7321 or maryann.petrocelli@kingcounty.gov.

Department of Natural Resources and Parks
Wastewater Treatment Division

Updated: July 3, 2008

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