GroundRosterLicensed Septic Contractors: Mason County, WA
13 licensed septic contractors based in Mason County. Every license number below is sourced from public licensing records, with a link to look it up yourself.
Grouped by the county of the address on each license record, which can be a mailing address, so it doesn't tell you where the business works. When the record names no county, we place it by ZIP code, then town.
Checked against Washington State Dept. of Health - Credential Search. Roster copy last refreshed 2026-08-17.
Towns in Mason County
All 5 towns named on the license records based here, with the number of listings in each, most first.
License classes on the Mason County records
Each class as the issuing agency prints it on the license record. A record that names more than one class counts once under each, so the rows can add up to more than 13.
| License class | Trade | Listings |
|---|---|---|
| On-Site Wastewater Designer | Septic | 9 |
| On-Site Wastewater Inspector | Septic | 4 |
Septic Contractors based in Mason County (13)
Alex Louis PaysseLicensed
Paula Joy JohnsonLicensed
Rhonda Elliott ThompsonLicensed
Callie BurtonLicensed
Dale Leon TahjaLicensed
Micah Thaniel HalversonLicensed
Anthony Owen DemieroLicensed
James L MedcalfLicensed
Dana L WoolliscroftLicensed
Steven Wayne PetersenLicensed
Jeffrey B WilmothLicensed
Dwight T SimpsonLicensed
Cindy E WaiteLicensed
Own one of these businesses? Find your listing and claim it.
Looking for a specific contractor? Search by name, business name, or license number.
Services in Mason County, with national cost ranges
Listings based in Mason County whose license class covers each service. Cost ranges are national; each links its cost guide.
| Service | Based in Mason County | National cost |
|---|---|---|
| Septic Tank Pumping | 0 | $250 to $600 |
| Septic System Installation | 0 | $3,600 to $12,500 |
| Septic Inspection | 4 | $150 to $900 |
| Septic System Design | 9 | Varies by site |
| Perc Test and Soil Evaluation | 0 | $250 to $1,000 |
None of the listings based in Mason County hold a license class we can match to septic tank pumping, septic system installation or perc test and soil evaluation. Ask any contractor whether they do this work, or try a nearby city.
Hiring a septic contractor in Mason County
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.
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.