Washington Septic Regulations: Chapter 246-272A WAC Explained

Sourced from the current text of chapter 246-272A WAC, section by section, plus WAC 246-272A-0013, -0015, -0270, -0340 and -0420, chapter 18.210 RCW, and rulemaking order WSR 24-06-046 — last checked August 2026.

What the rule is, and what it is not

Chapter 246-272A WAC is adopted by the State Board of Health, not by the Department of Health and not by the legislature. Its statutory authority runs through RCW 43.20.050(3) and 43.20.065 and chapters 70A.105 and 70A.110 RCW.

It is not the whole of the law that governs your system. Three other layers sit around it:

• Statute — chapter 70A.110 RCW creates the marine recovery area regime in the twelve Puget Sound counties; chapter 18.210 RCW licenses on-site sewage system designers; chapter 64.06 RCW governs seller disclosure.
• Local rules — adopted by your local board of health under WAC 246-272A-0013.
• Local management plans — required under WAC 246-272A-0015, which sets out the categories of area where a jurisdiction must identify increased public health risk.

Anyone telling you “the Washington septic rule says X” without asking which county you are in is giving you the floor and calling it the answer.

The one-way ratchet

This is the structural fact that explains almost every inconsistency you will find between counties. WAC 246-272A-0013 allows a local board of health to adopt its own on-site sewage rules provided they are “consistent with, and at least as stringent as this chapter”, and provided the department approves them before implementation. And then:

Nothing in this chapter shall prohibit the adoption and enforcement of more stringent regulations by a local board of health.

Stricter is always allowed. Looser never is. So when you find that a neighboring county requires something yours does not — an operational permit, a transfer inspection years before 2027, winter groundwater observation, dye testing — that is the rule working as designed, not an error.

The same asymmetry appears inside WAC 246-272A-0270(1)(k), where the local health officer may verify inspection results against the state standard and require additional inspections and requirements beyond it.

The whole chapter, section by section

Forty-three sections. We have not found this published as a plain list anywhere else, so here it is.

Five of these carry almost everything a homeowner ever needs: -0010 for what words mean, -0200 for when a permit is required, -0260 for what an inspection covers, -0270 for your own duties, and -0280 for what happens when it fails.

⚠ Two different things are called a waiver

This trips up everyone, including people who write about it.

If a designer tells you the county might “waive” something on a difficult lot, they mean -0420. If an estate agent tells you the county might “waive” the 2027 inspection, they mean -0270(1)(k). We have a whole page on the second one, because the conditions are harder than the summaries suggest.

The dates

The 2025 date is the one nobody talks about and it has a practical edge: a provider working entirely legally in 2024 is not automatically approved now. If you are assembling an inspection record, ask your jurisdiction for its approved list rather than taking a provider’s word.

Note also that 2027 is not the beginning of transfer inspections in Washington. Clallam, Jefferson, Whitman and Asotin already require one under their own ordinances — the ratchet again.

Statewide, or your county’s call?

The split that surprises people

Washington divides professional oversight in a way most states do not.

Your designer is licensed by the state, under chapter 18.210 RCW — a statewide license for on-site sewage system designers. Your installer, pumper and maintenance service provider are approved by the county, under WAC 246-272A-0340, jurisdiction by jurisdiction (with reciprocity permitted from another Washington jurisdiction).

The practical consequence: a designer’s credential travels across the state and an installer’s may not. If you are near a county line, ask before you assume. More on how this plays out in the permit process.

Where to read it yourself

Every section is free to read at the Washington State Legislature site — the citation format is app.leg.wa.gov/wac/default.aspx?cite=246-272A-0270, swapping the last four digits for the section you want from the table above. Each section ends with its own history line showing the rulemaking order and effective date, which is how you tell current text from a stale reprint.

That habit is worth more than any summary, including this one. Reprinted figures and superseded rule text are the single most common error in septic information online, and the history line is the two-second check.

This site is an independent information resource. We are not a health jurisdiction and we are not affiliated with the Washington State Department of Health or any county health department. Nothing here is legal advice. Where this page and your jurisdiction disagree, your jurisdiction is right — and we would like to know so we can fix this page.

Sources

• Chapter 246-272A WAC, on-site sewage systems — full chapter
• WAC 246-272A-0013, local rules — rule text
• WAC 246-272A-0015, local management plans — rule text
• WAC 246-272A-0270, owner responsibilities and the transfer requirement — rule text
• WAC 246-272A-0340, approval of installers, pumpers and maintenance service providers — rule text
• WAC 246-272A-0420, waivers — rule text
• Chapter 18.210 RCW, on-site wastewater treatment systems designers — statute
• Washington State Department of Health, On-site Sewage System Rule Revision — rule revision

Last reviewed August 2026 against the current text of chapter 246-272A WAC. The section list was read from the chapter index; the Snohomish date is news-sourced and flagged in place.