A Realtor’s Guide to the New Snohomish County Septic Rule

A Realtor’s Guide to the New Snohomish County Septic Rule (Bookmark This One)

You’ve got enough moving parts in a transaction already: inspections, appraisals, lenders, nervous clients, and that one seller who swears the roof is “only a few years old.” Starting November 1, 2026, Snohomish County adds one more: a required septic inspection before any home on septic can close.

The good news? This one is easy to manage if you get ahead of it. The agents who build it into their listing checklist will barely notice it. The ones who wait until they’re under contract are going to have some very uncomfortable phone calls.

We’re Above Grade Septic, and we’ve been doing time-of-sale septic inspections across Snohomish and King County since 2010. This guide is written for you, the agent: the facts you need, a timeline that works, and answers to the questions your clients are about to start asking.

The Rule in 60 Seconds

Here’s everything you need to know, in the order your clients will ask about it:

Why now: Washington’s septic code (WAC 246-272A-0270) requires every county to have time-of-sale inspections by February 1, 2027. Snohomish County, with about 84,000 septic systems and roughly 2,800 septic-home sales a year, is starting a few months early.

The Listing-Side Timeline That Keeps Closings on Track

The single best thing you can do for a seller on septic: order the inspection before the listing goes live. Here’s the timeline we recommend:

1. At the listing appointment: Ask, “Is the home on septic?” If the answer is “I think so” or “I’m not sure,” we can check county records for you.
2. 3–6 weeks before listing: Schedule the time-of-sale inspection. Since the report is good for 12 months, there’s no risk in going early.
3. If issues come up: The seller now has time to get repair quotes and decide whether to fix them before listing or price them in. Either option beats discovering a failed pump during the buyer’s option period.
4. Allow for the county review: The county can take up to 10 days to process the report. Don’t schedule anything that depends on it right up against that window.
5. At listing: “Septic inspected” is a selling point. Put it in the remarks and have the report ready for buyer agents.

Already under contract with no inspection? Call us right away. Between scheduling, a possible pumping, and the county review window, every day counts.

On the Buyer Side: What to Tell Your Clients

For buyers, the new rule is genuinely good news. They’ll know what they’re getting before they own it. Help them get the most out of it:

• Get the full report, not just a pass/fail. The details (tank size, last pumping, condition of pumps and floats, drainfield notes) tell the real story.
• Check the inspection date. A report can be up to a year old. If it’s on the older end, or there’s been a wet winter since, it’s fair to ask questions.
• Watch for issues passed along. If the seller chose not to repair something, it becomes your buyer’s problem after closing. Price it into the offer or negotiate a repair.
• Know the system type. A pressure, mound or ATU system has pumps and floats and needs an annual check-up. A gravity system is simpler. Your buyer should know which one they’re inheriting.
• Plan for ownership. Washington requires homeowners to keep up with septic inspections after they move in. Point buyers toward a local septic company for their first routine inspection.

Quick Answers to the Questions Your Clients Will Ask

Feel free to borrow these.

“Can’t my home inspector just look at the septic?” No. The rule requires a county-certified septic professional, and most general home inspectors aren’t certified for septic. It also matters which certification they hold. In Snohomish County, an O&M Level 1 certification comes with a pumper’s license and only covers gravity and pump-to-gravity systems. Pressure, mound, ATU and other advanced systems need an inspector with an O&M Level 2 certification, a separate license that covers every type of system. When you book, confirm the inspector is certified for the system on that property.

“Who pays for it?” The rule requires the inspection; it doesn’t dictate who pays. In practice it’s usually the seller, since it’s needed to sell, but like most things it’s negotiable.

“How much will it cost?” The county’s fee is $245 through 2027, plus the inspection itself. If the tank needs pumping, that’s an added cost too. Call us for a quote on your specific system.

“What if it fails?” A problem in the report doesn’t stop the sale. The seller can repair it and get an updated report, or leave it for the buyer to handle after closing. Either way, it’s disclosed.

“We just put in a new system. Do we still need this?” If it was installed within 12 months of the sale, no. That’s the one exemption.

“Will this slow down my closing?” Not if you plan ahead. Inspect before listing and it’s a non-issue.

Why Agents Work With Above Grade Septic

We’ve been doing time-of-sale inspections since 2010, long before they were required. We know what a closing timeline looks like, and we know you need answers, not excuses.

• We pull the county records before we show up, so there are no surprises about what’s in the ground.
• We coordinate pumping with our trusted partners when the inspection calls for it, so you’re not juggling another vendor.
• We write reports people can actually read. Your clients will understand what we found and what it means.
• We return calls. Revolutionary, we know.

Have a listing coming up on septic? Call us at (425) 954-7233 or email solutions@abovegradeseptic.com. Save our number now, before you need it — future you will thank you.

Above Grade Septic proudly serves Snohomish and King County, WA, with routine and time-of-sale inspections, septic repairs and maintenance, drainfield repair, system installations, and emergency service.

Sources

• Board of Health adopts new rules for septic system inspections — Everett Herald
• New septic inspection requirement coming to Snohomish County, November 1 — Lynnwood Times
• New Protections for Buyers of Homes with Septic Systems — Snohomish County Health Department