Snohomish County's property-transfer septic inspection rule took effect November 1, 2026. In general, a property with a septic system that changes hands now needs an inspection within 12 months of closing, with an exemption for newly installed systems. A Washington statewide version follows on February 1, 2027 under WAC 246-272A-0270.
This is a general explanation of the rule, not legal advice and not a finding about any specific property. Whether an inspection is required for your property, and what exactly it must cover, is something to check with Snohomish County or your title company.
What the inspection covers
A property-transfer inspection checks the tank and the system as a whole — condition, sludge and scum levels, baffles, the distribution box and drainfield, and any signs of failure such as wet areas or odours. The inspector files a Report of Property Transfer with the county, which carries a $245 county fee.
What it typically costs
As a guide only, a property-transfer inspection in Snohomish County typically runs $750, plus the $245 county fee — $995 before pumping, if pumping is also needed. That is a typical local range, not a quote — confirm the price and what is included before the visit. Routine inspections (not tied to a sale) typically run around $500.
Who pays, and when
Who pays for the inspection is a matter for the buyer and seller to agree — the rule itself does not set that. What matters is timing: the inspection needs to happen within 12 months of closing, so it is best arranged early in the sale rather than left to the last week, when a failed system can delay or derail a closing.
What to do if you are buying or selling
- Ask whether the property is on septic or city sewer — not every home in Snohomish County is on septic, and the rule only applies to septic properties.
- Ask when the system was last inspected and pumped, and whether there is a record with the county.
- If you are the seller, an inspection done early gives you time to fix anything it finds before closing.
- If you are the buyer, an inspection before you close is the cheapest way to find out what you are buying — a failed drainfield can cost far more than the inspection.
Why this matters now
About 84,000 private septic systems serve homes in Snohomish County, and roughly 2,800 septic properties change hands in a typical year. The rule is new, so many buyers and sellers are meeting it for the first time — and the inspectors who do this work are booking up.
Buying or selling a home on septic in Snohomish County? Ask about a property-transfer septic inspection — a local septic professional will get in touch, usually within an hour between 7am and 8pm Pacific.
Property-Transfer Septic Inspection in Snohomish County, WA