How to Check a California Plumber's License Before Hiring
A license check takes about two minutes and is the single best way to avoid a bad hire.
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The short answer
Ask for the plumber's contractor license number, then look it up on the Contractors State License Board website at cslb.ca.gov. The record shows whether the license is active, its classification, whether a bond is on file and whether there are disciplinary actions. It takes a couple of minutes, and you can do it while the plumber is on the way.
For plumbing work, the classification to look for is C-36, the plumbing contractor license. Other classifications may apply to related work, such as C-4 for boiler and hot water heating, but a plumber doing your job should hold a license that matches it.
What to check on the record
- The license status is active and not expired, suspended or revoked
- The classification matches the work, such as C-36 for plumbing
- The name on the license matches the name on the quote and the truck
- A contractor's bond is on file
- Workers' compensation coverage is shown, or an exemption is explained
- There are no serious complaints or disciplinary actions listed
When a license is required
California allows an unlicensed person to do small jobs only up to $1,000 in total, including labor and materials. That limit, raised from $500 by AB 2622 effective January 1, 2025, does not apply to work that needs a building permit or that involves hiring workers. Replacing a water heater, for example, needs a permit, so it needs a licensed contractor whatever the price.
Warning signs before you hire
Most bad hires give themselves away early.
| Sign | Why it is a problem | What to do |
|---|---|---|
| No license number offered | You cannot verify who is doing the work | Ask again, and move on if refused |
| A license that belongs to someone else | The person on your job may not be licensed | Check the name on the record |
| Large cash deposit demanded | Big upfront payments are a red flag | California limits deposits on home improvement contracts, so ask about the rules |
| No written quote or contract | There is nothing to hold anyone to | Get scope and price in writing |
| Pressure to decide on the spot | It leaves no time to compare | Take time, unless there is an active emergency |
| Refuses to pull a permit | The work will not be inspected | Ask why and check with the building office |
If you called a plumbing line
Some plumbing companies dispatch their own employees, and others pass requests to independent local contractors. Either way, the person who arrives must hold a valid license for the work. Ask for the license number before you agree to anything and look it up. That applies to us as well: the plumbers who take calls through this site are independent contractors, and you should check the one who comes to your door.
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Get it in writing
A good quote names the work, the materials, the price, the start and finish dates if they matter and who pulls the permit. Compare more than one bid when the job is not an emergency. See what drain cleaning costs and how to decide on a water heater for examples of what to ask.
Keep the contract, the receipt and the license number in one place. If a dispute comes up, the Contractors State License Board takes complaints, and its record of a contractor is public.
In an emergency
A burst pipe at midnight does not leave much time for research, but a two-minute check is still possible. Ask for the license number on the phone, look it up while you close the main valve, and confirm the name when the plumber arrives. If something does not match, do not let the work start.
What bonds and workers' compensation mean
A licensed contractor must carry a contractor's bond, which is a guarantee that can be claimed against if the contractor breaks the law or the contract, up to the bond amount. It is not insurance for your project, but it is a safety net. Workers' compensation covers the contractor's employees if they are hurt on the job. If a contractor has employees and no coverage, you can be pulled into a dispute if someone is injured at your home.
The license record on the state website shows both.
Questions to ask on the phone
- What is your contractor license number and classification?
- Will you pull the permit, and when is the inspection?
- Do you carry workers' compensation and liability insurance?
- Will you give me a written quote before any work starts?
- Who will actually come to the house, and will they show ID and their license?
- What is your warranty on the work and the parts?
If something goes wrong
Start by writing down what happened, with dates, photos and copies of the contract and payments. Give the contractor a written chance to fix it. If that does not work, the Contractors State License Board takes complaints and can look into unlicensed activity and license violations. A small claims court is another route for disputes over money. This is general information, so consult a lawyer or a consumer agency for advice about your case.
Questions about this topic
A contractor license from the Contractors State License Board, normally in the C-36 plumbing classification for plumbing work.
Go to cslb.ca.gov, use the license check, and enter the number or the business name.
Only up to $1,000 in total cost, and not when the work needs a permit or employees. A water heater replacement needs a permit.
Do not hire them. A licensed contractor has no reason to hide it.
The Contractors State License Board takes complaints about licensed and unlicensed contractors.
Related guides
Water Heater Permit in Sacramento County: What You Need
A same-for-same replacement usually needs a plumbing permit. Here is what the permit and inspection cover.
Who Pays the Plumber: Landlord or Tenant in California?
In most cases the landlord pays for plumbing that stops working. The exceptions and the steps to take are worth knowing.
Drain Cleaning Cost in Sacramento County, CA: What to Expect
National price ranges, the factors that move the bill and how to tell a fair quote from a padded one.
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