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The Public Health On-site Sewage System (OSS) Program helps to ensure that over 85,000 septic systems including 192 septic systems in Seattle are safe. Septic systems treat wastewater when homes and buildings are not connected to public sewer systems. The OSS Program provides educational, advisory and permitting services for owners of septic systems and certifications for several septic professionals.

2016 On-site Sewage System (OSS) plan update

Public Health is undertaking a public process to update its Onsite Sewage Systems Management Plan to incorporate new information, highlight current problems, confront new critical issues and more thoroughly address all OSS throughout King County.

Public Health is convening a Work Group, composed of representatives from key industry and homeowner stakeholders.

Learn more about the plan, Work Group goals, read public comments, access meeting materials and more.

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Contact us

Environmental Health Services
14350 SE Eastgate Way
Bellevue, WA 98007

Phone: 206-477-8050 (answered until 4:00 pm)

Office hours:

  • Monday, Tuesday, Wednesday & Friday:
    8:00 am – 4:00 pm

  • Thursday:
    9:00 am – 4:00 pm

Call our "Sanitarian of the Day" (SOD) for technical and general questions at 206-477-8177
The SOD is available Monday, Wednesday and Friday 8:00 am - 10:00 am only. If the sanitarian does not answer, he or she may be helping someone at the counter. Please leave a voice message and we will return your call as soon as possible.