Plumber Coverage in California: License, Bond and Comp Rules

Plumber insurance in California starts with what the state requires for your license. The Contractors State License Board (CSLB) requires a $25,000 contractor bond before a license is issued, and workers' compensation coverage if you have even one employee. From there, general liability and commercial auto for your work van are coverages many plumbing contractors look at to protect the business.

Picture a plumber in Pomona getting ready to take on a first employee and a second van. This guide walks through the license rules, the bond, workers' comp, and coverage basics.

Start With the C-36 Plumbing License

CSLB's C-36 Plumbing Contractor classification says: "A plumbing contractor provides a means for a supply of safe water, ample in volume and of suitable temperature for the purpose intended and the proper disposal of fluid waste from the premises in all structures and fixed works." The scope includes gas piping, water heaters, and safety devices such as backflow preventers and earthquake valves.

According to CSLB's license application steps, a license is needed when "the total cost (labor and materials) of one or more contracts on the project is $1,000 or more". Applicants need "at least four full years of experience at a journey level, or as a foreman, supervisor, or contractor".

Before CSLB issues the license, its issuing page lists items to submit, including a "Contractor bond or cashier's check of $25,000" and either a workers' compensation certificate or an "Exemption from workers' compensation, if no employees".

The $25,000 Contractor Bond

CSLB's bond requirements page states: "On January 1, 2023, the contractor license bond, bond of qualifying individual, and disciplinary bond, increased to $25,000."

CSLB explains who the bond is for: "The bond is filed for the benefit of consumers who may be damaged as a result of defective construction or other license law violations, and for the benefit of employees who have not been paid wages that are due to them."

A second bond may apply. CSLB says: "A Bond of Qualifying Individual is required if the license is qualified by a Responsible Managing Employee (RME)."

Workers' Comp When You Hire

CSLB's workers' compensation page is direct: "California law requires that employers, including those in the construction industry, carry workers' compensation insurance, even if they have only one employee." A contractor with no employees can file a signed exemption certifying that. CSLB also says you cannot file an exemption if "Your license is qualified by a Responsible Managing Employee (RME)".

CSLB lists certain classifications that must carry workers' comp whether or not they have employees: C-8 Concrete, C-20 HVAC, C-22 Asbestos Abatement, C-39 Roofing, and C-61/D-49 Tree Service. C-36 is not on that list, so for now plumbers with no employees can file an exemption. CSLB's December 2024 bulletin says licensees in all other trades "can continue to claim exemptions if they have no employees, until January 1, 2028". CSLB also warns: "Failure to maintain workers' compensation insurance coverage will result in the license being suspended."

The Department of Industrial Relations (DIR) describes the penalties. A stop order "prohibits the use of employee labor until coverage is obtained", and ignoring it "is a misdemeanor punishable by imprisonment in the county jail for up to 60 days, or by a fine of up to $10,000, or both". DIR also says: "You must post the 'notice to employees' poster in a conspicuous place at the work site."

How workers' comp premiums are figured

The California Department of Insurance (CDI) explains that classifications are "assigned codes by the Workers' Compensation Insurance Rating Bureau of California (WCIRB)". Then "The payroll for each classification is estimated and then multiplied (per each $100 of payroll) by the applicable rate."

General Liability Basics for Plumbers

CDI's commercial insurance guide calls Commercial General Liability (CGL) "the standard commercial liability policy used to insure businesses". The Insurance Information Institute (Triple-I) says bodily injury and property damage coverage protects against the insured's legal liability for injury or damage to others arising out of "non-professional negligent acts".

Know the limits of a CGL policy. Triple-I notes: "Workers compensation and employment practices liability insurance are excluded but can be purchased as separate policies." It also says "pollution liability is excluded and can be purchased as an endorsement". Triple-I adds that "this coverage is very limited, and high-risk businesses should consider purchasing a separate pollution liability policy". CDI advises: "There are major exclusions under a CGL policy so it is always important to read and understand all coverage exclusion."

If your business is an LLC, liability coverage is a license rule. CSLB's LLC page says: "Liability insurance with the cumulative limit of at least $1 million for licensees with five or fewer persons listed as members of the personnel of record is required."

Commercial Auto for Work Vans

CDI says: "Commercial automobile coverage can protect your company from any liability stemming from automobiles used in your business or any damage to the covered automobile." Triple-I's business vehicle guide adds: "If a vehicle is used primarily in business, there is likely no coverage under a personal auto policy."

Triple-I says "non-owned autos" liability can be added to a business auto policy, "which provides coverage when employees drive their own vehicles on business". Our post on the loading and unloading gap for California contractors covers one more issue for work trucks.

Plumber Insurance Checklist for California

Review these items:

1. License: Active C-36 license before bidding jobs of $1,000 or more.
2. Bond: $25,000 contractor bond on file, plus a qualifying individual bond if you use an RME.
3. Workers' comp: A certificate on file with CSLB once you hire, or, for now, an exemption if you have no employees.
4. Liability: Read the CGL exclusions, and meet the CSLB minimum if you are an LLC.
5. Vehicles: Business auto coverage for vans, and non-owned auto liability if employees drive their own cars.

Training a new hire? Our look at why some plumbing apprentices take longer may help.

Frequently Asked Questions

Do plumbers in California need workers' comp?

If you have employees, yes. CSLB says California law requires employers, including those in construction, to carry workers' compensation even with only one employee. For now, a plumber with no employees can file a signed exemption with CSLB. Letting coverage lapse results in license suspension, according to CSLB.

Is the contractor bond the same as liability coverage?

No. CSLB says the $25,000 bond is filed for the benefit of consumers damaged by defective construction or other license law violations, and for employees owed unpaid wages. General liability, as Triple-I describes it, covers the business's legal liability for bodily injury or property damage to others.

Does a personal auto policy cover a plumbing van?

Often not. Triple-I says if a vehicle is used primarily in business, there is likely no coverage under a personal auto policy. CDI notes commercial auto coverage can protect a company from liability stemming from automobiles used in the business or damage to the covered automobile.

Review Your Plumbing Business Coverage

Licensing rules set the minimum, and the rest depends on how your business runs. At Farmers Insurance - Young Douglas, we can review general liability, workers' comp, and commercial auto options with you, and our advice library has more guides for contractors. Coverage depends on your policy. Get a free quote and coverage review with our team.

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Written by LaMonte Douglas, owner of Young Douglas Insurance, a Farmers Insurance agency serving California from Ontario. CA License #4091974.

Sources (accessed September 23, 2026): CSLB: C-36 Plumbing Contractor, Before Applying for the Examination, Issuing My License, Bond Requirements, Workers' Compensation Requirements, Licenses for LLCs, Industry Bulletin 24-07, December 19, 2024; DIR, DWC FAQs for employers; CDI: Workers Compensation, Commercial Insurance guide, September 2023; Triple-I: Commercial general liability insurance, Business Vehicle Insurance.

Last updated: September 23, 2026.