How to find a licensed water pro in Sonoma County

By The Downspout · Updated Oct 11, 2026 · 1 min read

Match the job to the license, then look the license up on the state's site before you sign. It takes two minutes and the lookup is free.

Pick the license for the job

Drilling or repairing a well: C-57, Well Drilling Contractor.
Plumbing: C-36, Plumbing Contractor.
Landscaping and irrigation: C-27, Landscaping Contractor. Under California Business and Professions Code 7027.5, a C-27 can design and install exterior rainwater capture parts that are not attached to a structure. See our rain barrel guide.

If a job mixes trades, ask who holds which license. A tank tied into house plumbing is plumbing work.

Check the license

Open the State License Board license check.
Search by license number or business name.
Confirm the status is active and the classification matches the job.
Read any complaint disclosure shown.

The same site has a search for licensed contractors by ZIP code or city.

For a water test, use an accredited lab

The State Water Board publishes a map of labs accredited under its Environmental Laboratory Accreditation Program. Use the accredited lab map, then call the lab and ask how to collect the sample.

Before any permit work

Call Permit Sonoma first. The agency list has the number.

Local businesses

Our directory lists wells and pumps, plumbing, and graywater and landscape businesses. They are listings, not recommendations. Nothing on it is paid.

Sources

Checked 2026-10-11. Rules and programs change. If something here is out of date, the source above wins. Spot an error? See our corrections policy.