California Plumber License Requirements (2026)

The Class C-36 Plumbing Contractor license, issued by the California Contractors State License Board (CSLB), covers safe water supply and the disposal of fluid waste in structures and fixed works. California generally requires a contractor license when a project needs a permit, uses employee labor, or totals $1,000 or more. The qualifying individual must document four years of relevant experience, meet the CSLB examination requirements unless a waiver applies, file the required bond, and complete the issuance requirements before CSLB issues the license.

Regulatory Body

Contractors State License Board (CSLB) is the statutory authority responsible for issuing and enforcing this license under California Business & Professions Code §7000 et seq. (Contractors State License Law). The CSLB licenses and regulates contractors in 44 license classifications, investigates consumer complaints, enforces contractor license law, and prosecutes unlicensed activity through administrative, civil, and criminal action.

• Official portal: https://www.cslb.ca.gov/
• Address: 9821 Business Park Drive, Sacramento, CA 95827 (mailing: P.O. Box 26000, Sacramento, CA 95826)
• Phone: (800) 321-CSLB (2752) — in California; (916) 255-3900 — outside California

Eligibility Requirements

Applicants must be at least 18 years old. Applicants must provide a Social Security Number or Individual Taxpayer Identification Number (ITIN). No California residency requirement. Out-of-state applicants may apply.

Good moral character

Applicants must disclose any prior criminal conviction. CSLB conducts a criminal background investigation under Cal. B&P Code §480 and may deny licensure for offenses substantially related to the qualifications, functions, or duties of a contractor.

Background investigation

Mandatory fingerprinting through Live Scan (in-state) or hard cards (out-of-state). Results are reviewed by both the California Department of Justice and the Federal Bureau of Investigation.

Disqualifying conditions

• Felony convictions substantially related to construction or financial responsibility
• Prior license revocation in California or any other jurisdiction
• Outstanding court-ordered restitution to a contractor or homeowner

Experience and Education

The experience bar is 4 years of journeyman plumber, foreman, supervising employee, or contractor, and it must be backed by verifiable records — typically payroll, tax, project, or supervisor documentation covering the claimed period.

Accepted proof of experience or eligibility

• Certification of Work Experience in the current CSLB application, signed by a qualified person with direct knowledge of the work
• Employment and tax records kept available if CSLB requests supporting documentation during its review
• Official transcripts or apprenticeship-completion records when claiming permitted education or training credit

Education substitution

Up to three of the four years may be credited from accredited technical training, an approved plumbing apprenticeship, or post-secondary plumbing coursework.

Exam Requirements

Testing provider or authority: PSI Services LLC (under contract to CSLB). The following examination requirements cover the pathways described in this guide; follow each part's classification, waiver, and local-scope conditions. Unpublished format details do not remove an examination requirement:

• Law and Business — 115 questions, 210 minutes, passing score 72%
• Trade — Plumbing (C-36) — 115 questions, 210 minutes, passing score 72%

Examination fee: After CSLB accepts and refers the application for testing, PSI collects a separate fee for each examination. Confirm the current PSI fee when scheduling.

Retake policy: Applicants who fail an examination may reschedule for a fee. The application remains valid for 18 months from the date of acceptance.

Insurance and Bonds

Before the license is issued, the applicant must file a $25,000 contractor license surety bond in the form prescribed by the CSLB.

General liability

No statutory minimum for sole proprietors and corporations, but commercial general liability is required for limited liability company (LLC) licensees in the amount of $1,000,000 per occurrence (and an aggregate policy limit increased by $100,000 for each additional employee, up to a maximum of $5,000,000).

Workers' compensation

Workers' compensation insurance is mandatory for any licensee with one or more employees. Sole-owner licensees with no employees may file a Workers' Compensation Exemption Certification; certain license classifications cannot claim exemption.

Additional financial requirements

LLC applicants must additionally maintain an LLC employee/worker bond of $100,000 to protect employee wages and fringe benefits.

Fee Schedule

To turn these board fees into a realistic year-one budget — bond premium, liability insurance, and exam prep included — open the cost calculator preloaded for California plumber.

Renewal and Continuing Education

The California Class C-36 — Plumbing Contractor must be renewed every 2 years. The fee to renew is presently $450. Active sole-owner licenses renew every two years for $450. Non-sole-owner licenses renew for $700. Inactive licenses renew for $300 (sole) or $500 (non-sole). Renewal notices are mailed approximately 60 days before expiration. CSLB does not impose a continuing-education requirement, although the contractor is responsible for staying current on changes to the California Building Standards Code and the trade-specific code that governs the license classification.

Reciprocity

California grants no NASCLA reciprocity for this classification.

California does not accept NASCLA for the C-36 classification; the NASCLA waiver is limited to B-General Building. CSLB reciprocity applies only to listed equivalent classifications in Arizona, Louisiana, Mississippi, Nevada, or North Carolina, and CSLB retains discretion to require the trade examination.

Weighing more than one jurisdiction? The national hub compares published Plumber license requirements by state — exam, bond, fee, and experience thresholds side by side.

Plumber Licensing in Neighboring States

Contractors working near a state line, or weighing where to qualify first, should compare California's requirements against the bordering jurisdictions before committing to an application:

• Arizona Plumber License Requirements — Arizona Plumbing Contractor — C-37 Commercial / CR-37 Dual / Residential Plumbing Classifications
• Nevada Plumber License Requirements — Nevada C-1 Plumbing and Heating Contractor
• Oregon Plumber License Requirements — Oregon Journeyman Plumber and Plumbing Business (PB) License

Step-by-Step Application Roadmap

1. Form your business entity. Register the business with the California Secretary of State if operating as a corporation, LLC, or partnership.
2. Document four years of qualifying plumbing experience. Document four years within the prior 10 years at journey level or as a foreman, supervising employee, or contractor. A qualified person with firsthand knowledge must certify the experience; education or apprenticeship credit may cover up to three years.
3. File the Application for Original Contractor License. Submit Form 13A-1 with the $450 non-refundable application fee, specifying the C-36 classification.
4. Receive the Notice to Appear for Examination. PSI mails a Notice to Appear with scheduling instructions for both the Law & Business and the C-36 Trade examinations.
5. Pass both examinations. CSLB requires the Law and Business and C-36 trade examinations unless a waiver applies. Each computer-based examination is 3½ hours; the official C-36 guide covers planning and estimating, underground and rough systems, finish plumbing installations, service/repair/remodel work, and safety.
6. Submit fingerprints (Live Scan or hard cards). Pay the $32 California Department of Justice processing fee and the $17 FBI processing fee.
7. File the contractor bond and proof of insurance. File the $25,000 contractor surety bond, the workers' compensation certificate (or exemption), and (for LLCs) the $1,000,000 commercial general liability policy and $100,000 employee/worker bond.
8. Complete the Asbestos Open-Book Examination. Submit the completed asbestos open-book examination, included in the bond and fee letter.
9. Pay the initial license fee and receive your pocket card. Pay $200 (sole owner) or $350 (non-sole owner). CSLB issues the C-36 license number, wall certificate, and pocket card.

Application Checklist

Before submitting to CSLB, the applicant should have each of the following ready:

• Completed Application for Original Contractor License (Form 13A-1) — C-36 classification
• Certification of Work Experience documenting four years of qualifying C-36 experience within the prior 10 years
• $25,000 contractor license surety bond filed on the CSLB-prescribed form
• Workers' Compensation Certificate of Insurance — or signed Exemption Certification
• Completed Asbestos Open-Book Examination booklet

Progress is saved in this browser, so you can return to this checklist while your application is in flight.

Common Filing Mistakes

The errors below are the ones that most frequently cost California Plumber applicants time, drawn from the cited board guidance.

Vague experience verification

A common reason CSLB returns the Certification of Work Experience is generic phrasing such as "helped out on jobsites" or "assisted the foreman". The verifier must use specific journeyman-level trade terminology, and the dates must match the applicant's W-2 record.

Bond and license number mismatch

The business name and license number on the contractor's bond must correspond exactly to the CSLB record. Even a missing "Inc." or a transposed digit will cause CSLB to reject the bond and delay issuance until a corrected rider is filed by the surety.

Missing the asbestos open-book exam

Many applicants assume the bond and fee letter only requires the bond and the initial fee. The completed Asbestos Open-Book Examination is required in the same envelope. Forgetting it sends the application back to the bottom of the Issuance Unit queue.

Workers' compensation exemption errors

Sole owners with no employees may file an exemption, but certain classifications (notably C-39 Roofing) cannot. Filing an exemption when not eligible voids the entire issuance package.

Letting the application time out

Once CSLB accepts the application, the applicant has 18 months to pass both examinations and submit all post-exam documentation. Applicants who pause to re-take the exam multiple times frequently let the clock expire and have to refile from scratch (forfeiting the $450 application fee).

Study and Reference Materials

These materials are drawn from the regulator's own citations and the references applicants commonly use to prepare. CLR receives no compensation for listing them.

• C-36 Plumbing Study Guide (free PDF) — CSLB. Official outline of C-36 subject areas, weighting, sample questions, and suggested study resources.
• California Plumbing Code — California Building Standards Commission. Useful preparation resource for C-36 scope and code topics; the CSLB C-36 examination itself is closed book.
• CSLB Law and Business study materials — CSLB. Use CSLB’s official Law and Business materials and examination guidance rather than a commercial provider’s claimed outline.

Other California Trade Licenses

For a different California credential, see these companion guides published by CLR:

• California General Contractor License Requirements
• California Electrician License Requirements
• California HVAC Technician License Requirements
• California Roofing Contractor License Requirements
• California Painting Contractor License Requirements
• California Landscaping Contractor License Requirements
• California Masonry Contractor License Requirements
• California Concrete Contractor License Requirements
• California Carpentry Contractor License Requirements
• California Solar Installer License Requirements
• California Low-Voltage Technician License Requirements
• California Fire Sprinkler Contractor License Requirements
• California Home Inspector License Requirements
• California Pool Contractor License Requirements
• California Handyman License Requirements
• California Pest Control License Requirements
• California Septic Contractor License Requirements

Frequently Asked Questions

What does the C-36 plumbing license allow?

A C-36 contractor may install, maintain, and repair water supply systems, drain/waste/vent systems, gas piping, water heaters, and on-site waste disposal systems in residential, commercial, and industrial buildings. The classification is established under California Code of Regulations Title 16, Division 8, Article 3.

How is the C-36 trade exam structured?

The official C-36 study guide divides the closed-book, multiple-choice trade examination into Planning and Estimating (about 22%), Underground and Rough Systems (about 22%), Finish Plumbing Installations (about 20%), Service, Repair, and Remodel Plumbing Systems (about 19%), and Safety (about 17%).

What is the minimum bond required for a C-36 plumber?

A $25,000 contractor license bond is required, the same statewide CSLB amount in effect since January 1, 2023 under SB 607 and Cal. B&P Code §7071.6.

How long does the C-36 license remain valid?

CSLB licenses are issued for a two-year period and renew on a two-year cycle. Active sole-owner renewal is currently $450; non-sole-owner renewal is $700.

Does California accept NASCLA for the C-36 classification?

No. CSLB’s NASCLA Commercial General Builders waiver is limited to the B-General Building classification. C-36 applicants must meet the usual California examination requirements unless an applicable CSLB waiver or reciprocity determination applies.

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