Septic inspections in Thurston County
Get your system inspected for your county renewal, before a home sale, or when something isn't working right.
A septic inspection checks your tank, components and drain field and files a report with Thurston County. Homeowners need one when their county renewal comes due, when buying or selling, or when something seems off. The result tells you whether the system is working, whether the tank needs pumping and what needs attention.
Who can inspect a septic system in Thurston County?
A Thurston County certified septic professional can inspect any system. Some homeowners with qualifying conventional gravity, pressure distribution or mound systems can get certified to inspect their own. Starting in 2026, self-inspectors also need a satisfactory report from a certified professional every nine years. Complex systems, shared systems and systems with advanced treatment units usually need professional inspections, and some need monitoring or sampling too.
What does an inspection cover?
- Measuring the sludge and scum layers in the tank
- Checking baffles or tees, lids and risers
- Looking for leaks, cracks or water getting into the tank
- Checking pumps, floats and alarms on pressure and mound systems
- Walking the drain field for surfacing effluent, soggy spots or odors
- Filing the report in the county's online database
Do I need an inspection to sell my house?
Thurston County has requirements for septic systems when a property changes hands. Sellers who inspect early avoid surprises at closing, and buyers should ask for the report before they commit. You can look up past septic reports for a property in the county's online records. Check the county's time-of-transfer rules or ask your agent for the current requirements.
What affects the cost of an inspection?
- System type. Gravity systems are simplest. Pressure, mound and advanced treatment systems have more components to check.
- Lid access. Buried lids add digging time.
- Purpose. A home-sale inspection may be more detailed than a routine renewal.
- Pumping. If the tank needs pumping, that's usually a separate charge, often done on the same visit.
Prices come from the company doing the work, and a phone quote is only an estimate until someone has seen the system.
Tip: Keep a copy of your system's as-built drawing. It shows where the tank and field are, which saves time on every visit.
Where we connect you with help
Common questions
How do I know when my septic inspection is due?
Thurston County sends renewal notices for systems in its operations and maintenance program. The notice lists your due date and which inspection type applies.
Does an inspection include pumping?
Not necessarily. The inspection tells you whether the tank needs pumping. Many companies can do both on the same visit if it does.
Can I inspect my own septic system?
Some homeowners can after completing the county's certification, and only for certain system types and locations. Everyone else needs a certified septic professional.
Related services
More background: Thurston County septic guide.
Septic backing up or alarm going off?
Call now instead of sending a form. Backups are a same-day problem.