Licensed Septic Contractors in Washington

Washington lists 757 licensed septic contractors. They are based in 34 counties and 159 cities. 24 license classes appear, covering roles such as installation / repair, design and inspection.

Checked against Washington State Dept. of Health - Credential Search, Spokane Regional Health District - Permitted OSS Installers, Snohomish Health District - Certified Pumpers, Installers & M&M Specialists and King County Public Health - Master Installers (OSS). Roster copy last refreshed 2026-08-19.

Browse by county or request free quotes.

Septic (onsite wastewater) contractors handle everything from routine septic tank pumping and cleaning to repairs, inspections, and new system installation. States license each role separately (a pumper is not necessarily licensed to install, and vice versa), so match the license class to the job.

Counties with the most listings based there

All 34 counties

Browse Washington by county

Each listing sits under the county of the address on its license record, which can be a mailing address. 34 counties have listings based there.

Cities with the most listings based there

Septic Pumpers by city in Washington

Septic Tank Pumping cost guide

Septic Installers by city in Washington

Septic System Installation cost guide

Septic Inspectors by city in Washington

Septic Inspection cost guide

Septic Designers by city in Washington

Septic System Design cost guide

Don't see your county? Search by ZIPSearch

Looking for a specific contractor? Search by name, business name, or license number.

Hiring a septic contractor in Washington

Before you sign anything: confirm the license on this page is still active with the agency that issued it, ask for proof of insurance, and get at least three written quotes; pricing on this work varies widely by site conditions.

How do I check a septic contractor's license in Washington?

Use the license search to find the listing by name, business name, or license number, then confirm it with the agency that issued the license. Every listing links to the roster it came from.

What does septic pumping, cleaning, repair, inspection, or installation work cost in Washington?

Our cost guides give national ranges for septic tank pumping and cleaning, septic repairs, inspections, and new system installation. Site conditions, access, and local demand set the real number, so get at least three written quotes from licensed septic contractors in Washington.

Is a permit required?

Usually, for a new system or well and for most repairs. The state or county health authority sets the rules, so ask the contractor which permit the job needs and whether pulling it is included in the quote.

Licensed in Washington, based in another state

1 septic contractor holds a Washington license but the address on the license record is in another state, so they aren't under a Washington county.

Listings without a county

319 listings have no county we could place: the license record gives none, and its ZIP code or town doesn't settle one. Search by ZIP, or browse by the town on the record:

Where this Washington data comes from

• Washington State Dept. of Health - Credential Search · source page
• Spokane Regional Health District - Permitted OSS Installers · source page
• Snohomish Health District - Certified Pumpers, Installers & M&M Specialists · source page
• King County Public Health - Master Installers (OSS) · source page