Thurston County septic guide (2026)
What the county requires of septic owners, what changed in 2026, and where to find your system's records.
Updated September 30, 2026. This guide is general information, not legal or engineering advice. Rules change, so confirm with the agency listed before you start work.
Who does this apply to?
Any property in Thurston County served by an on-site sewage system (septic system) rather than city sewer. That includes much of the rural county and many homes on the peninsulas and around the lakes.
Key rules at a glance
| Topic | What the county says |
|---|---|
| Inspections | Systems in the operations and maintenance program need inspections on the schedule shown in your renewal notice. |
| Who can inspect | A Thurston County certified septic professional, or a certified homeowner for qualifying gravity, pressure distribution and mound systems. |
| 2026 change | From January 1, 2026, self-inspectors must also obtain a satisfactory report from a certified septic professional every 9 years. |
| Pumping | Pump when the scum and sludge layers are thick enough to need it. The county offers a stick-test brochure to help measure them. |
| Reports | Reports are submitted to OnlineRME, a public database where you can look up reports for your property. |
| Selling a home | The county has a "time of transfer" process that applies when a home with septic is sold. |
How do I find my system's records?
Search your address in the county's online septic records (OnlineRME) to see inspection and pumping reports that professionals have filed. The county can also help you find your system's as-built drawing, which shows where the tank and drain field are.
What are shellfish protection districts and marine recovery areas?
Thurston County's inlets support commercial and recreational shellfish harvest, and failing septic systems are one source of the bacteria that close beaches. The Henderson Inlet and Nisqually Reach shellfish protection district was formed in 2001 after the state downgraded shellfish growing areas because of bacterial pollution. The district covers the whole watershed, and parts of it were designated marine recovery areas to target pollution from septic systems. Septic owners inside those boundaries pay an annual charge through property taxes that funds extra monitoring and programs such as septic riser rebates.
Is there help paying for repairs?
The county's septic pages list a Craft3 loan program for septic repairs and replacements. Call the county's septic help line to ask what's currently available for your situation.
Who do I call at the county?
- Septic help line: (360) 867-2669
- General questions or a failing system: (360) 867-2673
How do I keep my system healthy?
- Keep up with inspections and pump when the inspection says to.
- Spread out laundry loads and fix leaking fixtures.
- Keep wipes, grease, paint and chemicals out of drains.
- Keep vehicles, livestock and new structures off the tank and drain field.
- Plant only grass over the field; tree and shrub roots invade pipes.
- Add risers so future service doesn't start with digging.
Common questions
Do I have to pump my septic tank on a schedule in Thurston County?
No fixed schedule applies to every home. The county's guidance is to pump when the inspection shows the scum and sludge layers are thick enough to need it.
What changed for septic self-inspectors in 2026?
Starting January 1, 2026, Thurston County requires homeowners who inspect their own systems to also get a satisfactory report from a certified septic professional every 9 years.
Where can I see past septic reports for a property?
Reports filed by septic professionals are submitted to OnlineRME, a public database the county uses. You can look up a property there.