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King County Washington home

Vashon-Maury Island Gravity Septic Self-Check Pilot Program

Conduct routine maintenance inspections on your own

The Gravity Septic Self-Check Pilot Program, launching in March 2027, helps gravity septic system owners on Vashon-Maury Island inspect their own systems, reducing the cost of inspections. This is a pilot program that will only be in place until early 2028 unless additional funding is obtained.

Short URL: kingcounty.gov/septic/selfcheck

Program overview

Eligible gravity septic system owners can use the program to conduct your own maintenance inspection instead of hiring a certified maintainer for every inspection. State and county law requires gravity systems to be inspected every three years.

After completing the program, you can alternate self-check inspections with certified maintainer inspections. For example, if you do a self-check inspection this year, you will need to have a certified maintainer conduct your routine maintenance inspection in three years.

Self-check inspections can only be used for routine maintenance inspections. They do not replace inspections needed for:

  • Real estate transfers
  • Building permit applications
  • Marine Recovery Area requirements
  • Commercial properties (like a restaurant)
  • Community septic systems

Am I eligible for the program?

You’re eligible if the below is true:

  1. You own the property.
  2. The property is on Vashon Maury-Island.
  3. The system is a conventional gravity septic system without a pump.
  4. The system has an approved permit on file.
  5. The system only has one or two connections.
  6. The system is on the property that it serves.
  7. The septic record drawing ("as-built") or site sketch is on record. Site drawings can be found online at Septic Records.
  8. A certified septic maintainer completed a routine inspection within the last 6 years. You can find the inspection history at: Septic Records.

How to complete the Self-check Program

  1. Apply for the program to confirm your eligibility: Gravity Septic System Self-Check Program Application. After we review your application, we will email about your eligibility. 
  2. Take a class and pass the exam. Register and attend an in-person class to learn septic system maintenance basics, self-check program details, and take a Septic-Self-Check Exam. 
  3. Conduct a self-check inspection. Using the resources provided in the class, conduct a self-check and submit the report to Public Health within 30 days of the self-check. Broadly, the report will ask:
    • Does the tank need to be pumped? 
    • Did you clean the outlet baffle filter cleaned? 
    • Is the tank lid secure? 
    • Does your septic system have signs of failure?
  4. After conducting the self-check, you are responsible for conducting all necessary maintenance and repairs as required by the code.

Note that if you want to do a dye test to confirm no sewage is leaking out of your system, contact Public Health. This isn’t required. Public Health can provide guidance on this process and, as funding allows, dye packets to perform the test.

When to get help

Older systems vary in their configuration and construction. In the past, there weren’t standards for septic systems, and permits weren’t required. This means there are some older homes where a system was installed years ago but the location and function is unknown. This doesn’t mean a system is not legal or failed; it just means the homeowner should get the help of a licensed Operations & Maintenance Specialist for the inspection.

You should also hire a licensed Operations & Maintenance Specialist if your system doesn’t have easy access or if the location is difficult to determine.