King County Comprehensive Plan 2008 – Chapter 4 – Page 53

Human waste contains high levels of nutrients and pathogens. These pollutants can enter Puget Sound waters from a variety of sources including septic systems. A number of properties on Vashon-Maury Islands have on-site sewage systems that pre-date regulatory oversight and are undocumented. Washington State Department of Health surveys have indicated that failing systems are a significant problem in some areas of the Vashon-Maury Island shoreline. Public Health – Seattle & King County (Public Health) is responsible for assuring that onsite sewage systems in King County meet state and local regulations. In addition, Public Health is required to identify areas where marine water quality is threatened or impaired as a result of contamination from onsite sewage systems, to designate these areas as Marine Recovery Areas (MRAs), to develop a plan to identify failed septic systems within the MRAs, and to assure that these systems are repaired and maintained. The ability to install new systems is often severely constrained in the shoreline, due to small lot size, topography, and soils. In some cases, community treatment systems are needed to effectively treat waste.

E-479 King County should work with landowners, the state Department of Health, sewer districts, and the Puget Sound Partnership to develop more effective strategies and additional resources for addressing failing septic systems in constrained shoreline environments.