Snohomish County, WA
Frequently asked questions
Plain answers to the questions we hear most about septic inspection, pumping, and repair in Snohomish County. Prices are guidance only, never a quote. Nothing here is legal advice, and nothing here diagnoses a problem with your system — only a provider who has seen it can do that.
FAQ
What does the Snohomish County property-transfer septic inspection rule require?
In general, Snohomish County's property-transfer septic inspection rule, which took effect November 1, 2026, requires an inspection by a certified professional within 12 months of closing when a property with a septic system changes hands, with a Report of Property Transfer filed with the county. Systems installed within the previous 12 months are exempt. A Washington statewide rule follows on February 1, 2027 (WAC 246-272A-0270). This is a general explanation, not legal advice: whether an inspection is required for your property, and exactly what it must cover, is something to check with Snohomish County or your title company.
How often should a septic tank be pumped?
As a general guide, most septic tanks need pumping every 3–5 years, depending on household size and tank size. More people and a smaller tank mean more frequent pumping. Slow drains, sewage smells, wet areas over the drainfield, and sewage backing up are common warning signs that a tank is overdue.
What are signs a septic system is failing?
Slow drains, sewage smells near the tank or drainfield, wet or unusually green areas over the drainfield, gurgling pipes, and sewage backing up into the house are common warning signs. If sewage is backing up into your home, do not use this form — call a local emergency septic provider directly right away.
How much does a septic inspection cost in Snohomish County?
As guidance only, never a quote: a routine inspection typically runs around $500, and a property-transfer inspection typically runs $750 plus the $245 county Report of Property Transfer fee — $995 before pumping, if pumping is also needed. A combined inspection and pumping visit is often budgeted at $1,000–$1,500. Only the provider can confirm a price for your property.
Who pays for the property-transfer inspection?
The county rule does not set who pays — that is a matter for the buyer and seller to agree, usually as part of the sale. 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.