GroundRosterLicensed Well and Septic Contractors: Marin County, CA
9 licensed well and septic pros based in Marin 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 California Contractors State License Board (CSLB). Roster copy last refreshed 2026-08-17.
Towns in Marin County
All 5 towns named on the license records based here, with the number of listings in each, most first.
License classes on the Marin 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 9.
| License class | Trade | Listings |
|---|---|---|
| Sanitation System Contractor (C-42) | Septic | 6 |
| Well Drilling Contractor (C-57) | Well | 3 |
Septic Contractors based in Marin County (6)
Cervantes Sil ELicensed
Maggiora And Ghilotti INCLicensed
Ghilotti Bros INCLicensed
City Sewer Pumping INCLicensed
Roto Rooter PlumbersLicensed
Ghilotti Gary Engineering Contractor
Water Well Contractors based in Marin County (3)
R W R Construction INCLicensed
S O S ILicensed
American Construction And Supply INCLicensed
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Services in Marin County, with national cost ranges
Listings based in Marin County whose license class covers each service. Cost ranges are national; each links its cost guide.
| Service | Based in Marin County | National cost |
|---|---|---|
| Septic Tank Pumping | 0 | $250 to $600 |
| Septic System Installation | 6 | $3,600 to $12,500 |
| Septic Inspection | 0 | $150 to $900 |
| Septic System Design | 0 | Varies by site |
| Perc Test and Soil Evaluation | 0 | $250 to $1,000 |
| Well Drilling | 3 | $5,500 to $35,000 |
| Well Pump Repair | 0 | $1,000 to $2,500 |
None of the listings based in Marin County hold a license class we can match to septic tank pumping, septic inspection, septic system design, perc test and soil evaluation or well pump repair. Ask any contractor whether they do this work, or try a nearby city.
Hiring a well and septic professional in Marin County
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.
Do I need a permit for well or septic work in California?