How to Hire a Licensed Plumber in California: A 2026 Checklist

California is one of the stricter states for contractor licensing. Plumbing contractors are licensed statewide by the Contractors State License Board (CSLB) under the Contractors State License Law (Cal. Bus. & Prof. Code section 7000 et seq.): any plumbing job of $1,000 or more in combined labor and materials requires an active license with the C-36 Plumbing Contractor classification, a contractor bond on file, and workers'-compensation coverage when the company has employees. Many cities also require the company to register locally before pulling permits.

A licensed contractor has passed the CSLB's trade and law exams and carries accountability if something goes wrong. An unlicensed handyman may be cheaper today and far more expensive after a failed repair floods a finished home -- and in California, unlicensed contracting over the $1,000 threshold is illegal.

Run through these seven items for every plumber you are considering.

1. 1License. Ask for the company's CSLB license number and confirm it carries the C-36 Plumbing Contractor classification.
2. 2Insurance and bond. Confirm general liability insurance and bonding, and ask for a certificate if the job is large.
3. 3Written estimate. Require an itemized, written estimate before work begins. See typical numbers in our drain cleaning cost guide.
4. 4Reputation. Read recent reviews and ask for references on bigger jobs.
5. 5Permits. For water heaters, repipes, sewer work, and gas lines, a permit and inspection are often required. A pro who skips permits is a warning sign.
6. 6Warranty. Ask what is warrantied, for how long, and whether it covers both parts and labor.
7. 7Payment terms. Reasonable deposits are normal on large jobs. Full payment in cash before any work is not.

You do not have to take a plumber's word for it. The state publishes a public license lookup.

State (CSLB) license

Search the CSLB License Check for the license number the plumber gives you, and confirm the business name matches, the C-36 classification is listed, the license status is ACTIVE, and the bond and workers'-comp lines are current.

Local registration and permits

Most California cities require plumbing companies to register with the local permitting office before working inside city limits, and your city's permit portal will show whether a permit was actually pulled for your job. Every business in our directory shows the public registry data we matched it to, and you can read how we do that on our verification page.

• Refuses to provide a license number or proof of insurance
• Will only give a price in person and pressures you to decide on the spot
• Demands full payment in cash before starting
• Has no written estimate or contract
• Wants to skip permits on work that legally needs them
• Quotes a price far below every other bid, which often means an unlicensed crew

If you are dealing with a true emergency such as a burst pipe, the pressure is real, but the fundamentals still apply. Our plumbing emergency guide explains how to act fast without getting taken advantage of.

A short conversation prevents most disputes.

• Is this price flat-rate or hourly, and what could change it?
• Who pulls the permit, and is the inspection included?
• What warranty comes with the parts and the labor?
• Will you haul away the old water heater, fixture, or debris?
• Who is the actual licensed person on site, not just the company name?

Keep the signed estimate, the permit, and the final invoice together. If a repair fails inside the warranty window, those documents are your leverage.

When you are ready, you can browse licensed California plumbers by city, or learn the early signs you need a plumber so you call before a small issue becomes an emergency.