Frequently asked questions

Yes, starting November 1, 2026, Snohomish County requires a certified septic inspection before a property with a septic system is sold, unless the system was installed within the past 12 months.

12 months from the date of inspection, unless the system's conditions change in the meantime.

It's the Washington State administrative rule requiring on-site sewage (septic) system evaluations at time of property transfer. It becomes mandatory statewide by February 1, 2027. Snohomish County's new local rule, effective November 1, 2026, brings the county into compliance with this state mandate ahead of that deadline.

The county's application/report fee is $245 for 2026–2027 (rising to $255 in 2027–2028), separate from the certified inspector's own service fee, which typically runs $300–$500, plus $400–$700 more if the tank needs pumping. See the full cost guide.

Systems installed within 12 months of the property sale are exempt, since they've already been evaluated as part of installation and permitting.

The rule places the inspection obligation on the seller, and in practice sellers typically pay for it, similar to other pre-listing inspections. This can be negotiated differently in a specific purchase and sale agreement. More detail on who pays for what.

A failing or marginal result doesn't automatically block the sale. Typical paths are repairing before closing, negotiating a price credit, or disclosing the condition to the buyer, depending on your purchase agreement and the buyer's lender requirements. Reported details on how unresolved deficiencies are handled at closing have not yet been fully confirmed against the county's official code language — we recommend confirming directly with the Health Department or your agent. More on what each rating means.

Up to 10 days, according to reporting on the new rule, so it's worth building that into your closing timeline rather than scheduling an inspection at the last minute.

No — this specific rule is a point-of-sale requirement tied to a property transfer. It doesn't create a new routine inspection schedule for homeowners who aren't selling, though Snohomish County has separate long-standing operation and maintenance requirements for certain system types.

Snohomish County Health Department maintains an online database called OnlineRME where you can search by parcel or address. If nothing comes up, older systems sometimes have undigitized paper records the Health Department can look up directly. Full walkthrough here.