How to Get Your Plumbing Contractor License in California

If you want to run plumbing jobs in California as a contractor, the license you need is the C-36 Plumbing Contractor classification from the Contractors State License Board. California has a limited exemption for work under $1,000 when no permit is required and no employees are used, but nearly every commercial plumbing job will require a license.

Here’s how to get it.

What the C-36 License Covers

The C-36 is defined under California Code of Regulations, Title 16, Division 8, Article 3. A plumbing contractor provides a means for a supply of safe water and the proper disposal of fluid waste from structures and fixed works. The classification is broader than many people expect.

It covers the complete removal of waste from premises, construction of on-site disposal systems, and piping, storage tanks, and venting for gas and liquid supply, including medical, dental, commercial, and industrial uses. It also covers gas appliances, flues, and gas connections for most systems, including suspended space heating units; water and gas piping from the property owner’s side of the utility meter to the structure; installation of equipment to heat water or fluids, including solar thermal equipment; and maintenance and replacement of health and safety devices like gas earthquake valves, backflow preventers, and water conditioning equipment.

One explicit carve-out: forced warm air units are not included. That work falls under the C-20 classification.

Do Your Employees Need a Plumbing License?

California does not have a statewide journeyman plumber certification for individual workers, unlike the electrician certification program administered by the Department of Industrial Relations for C-10 contractors. The C-36 licenses the contracting business and its qualifying individual. Your employees don’t need a separate state-issued plumber’s license to work for you, though local jurisdictions and utilities may have their own permit or inspection requirements.

Step 1: Meet the California C-36 Experience Requirements

CSLB requires four years of experience in the plumbing trade within the ten years immediately before you apply. Not four years of employment in the industry. Four years at journey level or above. (CSLB)

For a C-36 specifically, CSLB interprets this as performing plumbing work every day for four full years, at approximately eight hours per day. (CSLB) A property manager who fixes a leaky faucet every few weeks doesn’t qualify, even if they’ve been doing it for years. The experience has to be in the trade, consistently.

Journey level means you’re a fully qualified plumber who can perform the work without supervision, or someone who completed a formal apprenticeship program. Foremen, supervising employees, licensed contractors, and owner-builders with verifiable hands-on experience also qualify. Time working as an apprentice, helper, or laborer does not count as journey-level experience. However, qualifying apprenticeship training can earn credit toward the four-year requirement, as explained below.

CSLB notes that a plumbing apprenticeship typically runs five years, and that applicants may need additional journeyman experience depending on how their experience is documented. If you completed an apprenticeship and plan to apply soon after, expect CSLB to assess what combination of training credit and journey-level time you can demonstrate.

You can get up to three years of credit for apprenticeship training, technical training, or education, but at least one year has to be actual hands-on work at journey level. The education credits break down like this:

Up to 1.5 years for an AA degree in building or construction management. Up to two years for a four-year degree in a field like engineering, business, mathematics, or physics. The full three years if you hold a Certificate of Completion of Apprenticeship from an accredited program, or a four-year degree in construction technology or a directly related engineering field.

Every experience claim has to be verified by someone with firsthand knowledge: an employer, a contractor, a foreman, a union rep, or a building inspector. They sign off on the Certification of Work Experience form. CSLB can ask for supporting documentation at any point. If you can’t produce it, your application is at risk.

Step 2: Submit Your Application

Once you’ve got the experience, you apply through CSLB’s exam application process. Sole-owner applicants can apply online. Other business structures may use a printable application. Either way, include the Certification of Work Experience form (13A-11) and pay the $450 application processing fee.

Don’t submit bonds or your initial license fee with the application. Those come later.

You can only apply for one classification at a time when an exam is required. Get the C-36 first, then add classifications later if needed.

CSLB will send you an acknowledgment letter with an Application Fee Number and a PIN. Use those to track your application status online.

Step 3: Get Fingerprinted

After your application is accepted, you’ll get instructions to complete a Live Scan fingerprinting. CSLB runs a criminal background review as part of the process. This happens before you’re scheduled for the exams.

Step 4: Study and Pass the Exams

CSLB has a C-36 study guide on their site. Use it.

After CSLB accepts your application, you’ll receive a Notice to Schedule an Examination. You’ll generally need to pass two exams: the C-36 trade exam and the Law and Business exam. Both are administered by PSI, CSLB’s testing vendor. You contact PSI directly to schedule your test dates.

You have 18 months from application acceptance to pass the required exams. If you pass one and fail the other, you only have to retake the one you failed, and that passing score stays valid for five years.

Don’t let the 18-month window make you complacent. Processing times fluctuate, and the closer you get to that deadline without passing, the more pressure you’re under to reschedule.

Step 5: Get Your License Issued

Pass the exams, and CSLB’s Issuance Unit sends you a bond and fee letter. That letter tells you exactly what to submit. Here’s what’s typically required:

Initial license fee. $200 for sole owners. $350 for any other business type. This covers the first two years.

Contractor’s bond. You need a $25,000 contractor’s bond filed with CSLB. Buy it through a licensed surety company. CSLB doesn’t issue bonds. The $25,000 is the bond amount, not the premium you pay to the surety. Depending on how your business is structured and who serves as your qualifier, a separate $25,000 Bond of Qualifying Individual may also be required.

Asbestos open-book exam. Every new applicant has to complete this before CSLB can issue a license, per Business and Professions Code section 7058.5. It’s not a certification to do asbestos work. It’s a knowledge check on how to handle situations where asbestos might be present on a job.

Workers’ compensation. If you have employees, you need proof of coverage. C-36 is not among the classifications that must carry coverage regardless of employee status, so if you have no employees, you can file a workers’ compensation exemption instead. If an RME qualifies your license, the exemption isn’t available. (CSLB)

Once everything’s in, CSLB issues your license. You’ll get a wall certificate (required to be displayed in your main office) and a pocket card to carry.

How Much Does a C-36 License Cost?

The bond amount and the bond premium are not the same thing. The $25,000 is what CSLB requires the bond to cover. What you pay a surety company for that bond depends on your credit and the surety’s rates.

Keeping It Active

An active C-36 license is good for two years and renews every two years. While active, you have to maintain your contractor’s bond, the Bond of Qualifying Individual if required, and workers’ comp coverage if you have employees. Let any of those lapse and your license can be suspended.

You can hold an inactive license if you’re not taking on work. It renews on a four-year cycle and doesn’t require the bond or workers’ comp, but you can’t bid or contract while it’s inactive.

Once You’re Licensed

Your license number has to appear on construction contracts, subcontracts, bids, and advertising under California Business and Professions Code section 7030.5. Beyond the license number, California sets specific requirements for what goes in a home improvement contract — downpayment caps, cancellation notices, and mandatory disclosures. California’s contractor invoice and contract requirements covers what you need on paper once you’re working.

Tools like Cinderblock automatically carry your license number onto estimates and invoices, so you’re not manually entering it every time you send something to a client.

This article is for general informational purposes only and does not constitute legal advice. Licensing requirements can change. Consult the relevant licensing authority or a qualified attorney for guidance specific to your situation.