Washington's New Septic Inspection Law: What Changes Starting February 2027

Right now, whether a septic-served home needs an inspection before it can be sold in Washington depends heavily on which county it's in. Some counties require one, some don't, and the rules aren't identical where they do exist. That patchwork is going away.

What's changing

Starting February 1, 2027, Washington will require septic-served properties to get a property-transfer inspection completed by a third-party inspector authorized by the local health officer before the sale or deed transfer goes through. It's designed to standardize a rule that currently varies from county to county across the state.

Why it's happening

Failing septic systems are expensive surprises for new homeowners and a real public health concern when they're not caught early. A consistent statewide inspection requirement closes the gap in counties that currently don't require anything at time of sale, so buyers get the same baseline information no matter where in Washington they're buying.

What this means if you're planning to sell

• If your county doesn't currently require an inspection, it will after February 1, 2027 — plan for it even if you haven't had to before
• Inspections that turn up issues take time to resolve, so getting one done well ahead of listing gives you room to fix problems on your own timeline instead of a buyer's
• The inspector has to be authorized by the local health officer — not just any contractor — so it's worth confirming credentials before you book

How we can help

We're OSS certified and already perform real estate inspections across Grays Harbor, Thurston, and Lewis Counties under the current county-by-county rules. If you're thinking about selling anytime in the next couple of years, getting a baseline inspection now — before the statewide requirement kicks in and everyone's booking at once — is a good way to get ahead of it.