Selling a home on septic in Snohomish County? The rules just changed.

Starting November 1, 2026, anyone selling a property with a septic system in Snohomish County has to complete a set of septic requirements before closing. A new Washington State rule requires every county to have a program like this by February 2027, and Snohomish County went first. Here is what sellers, buyers and agents need to know, in plain English.

The three steps for sellers

1. Get the system inspected (and pumped if recommended)

• You need a full septic inspection by a certified septic contractor within the past 12 months.
• If the inspection report recommends pumping, the tank also has to be pumped by a certified contractor. If it doesn’t, pumping isn’t required.
• Check whether an as-built (the drawing of your system) is on file. Our as-built lookup guide shows how. If one is on file, there is nothing more to do here.
• No as-built? The county says not to hire a septic designer to make one. Instead, a certified septic contractor completes an On-Site Sewage System Site Plan, which you submit with your application.
• If the as-built is wrong or out of date, the differences get noted on the inspection report.

2. Submit a Report of Property Transfer (RPT)

You apply and pay the fee through the Health Department’s online portal (log in, open the On-Site Sewage tab, then choose Report of Property Transfer Application). The Health Department reviews the application and your septic records, then sends the report back to you with or without deficiencies noted.

If the deficiencies include surfacing sewage or an immediate health or safety hazard, the county will also visit the site and may start enforcement. Unsecured or inadequate tank lids count as a hazard: a cracked lid, or a pallet or sheet metal over a tank opening. If you fix the problems, email SHD-EHQ@snoco.org and ask for the report to be reissued.

3. Give the buyer the paperwork at closing

• The Report of Property Transfer reviewed by the Health Department (good for 12 months from acceptance)
• Your septic maintenance records
• The seller’s disclosure statement (chapter 64.06 RCW)

What we recommend

• Start before you list. Book the inspection four to six weeks out, so there is time for pumping, a site plan or repairs without holding up closing.
• Check your lids now. Loose or makeshift lids are one of the easiest problems to fix and one of the few that trigger enforcement. Risers and secure lids solve it.
• Gather your records. Past pumping and inspection reports go to the buyer anyway, and they speed up the review.
• Use your rebates. Savvy Septic rebates still apply to inspections, pumping, risers and minor repairs done for a sale (residential only, after the free online workshop).

For buyers

You should receive the Health Department’s Report of Property Transfer, the maintenance records and the seller’s disclosure before closing. Read the deficiencies section closely. If a seller doesn’t fix surfacing sewage or an immediate hazard, the county moves enforcement to the new owner, which would be you.

How Septic Response helps

We do septic inspections and pumping across Snohomish County from our Woodinville office, and we file inspection reports within 24 hours so your sale stays on schedule. If your system has no as-built, ask us about the site plan when you book. Selling in King County instead? It has its own time-of-sale inspection rule.

Quick answers

Source: Snohomish County Health Department, Property Transfer (revised 11/1/26) and Savvy Septic Program. Rules can change, so confirm the details with the Health Department (425-339-5250) before you close.