How much does insurance cost for a plumbing contractor?

Plumbing on the official comp schedules

Comp for plumbers costs far less than for roofers or framers, but it is not cheap office-class pricing. Three monopolistic state funds publish the actual rate, not just a bureau loss cost. Ohio uses NCCI-based codes, where plumbing is class 5183, “Plumbing NOC and Drivers”⁠¹. Washington has its own class 0306, “Plumbing”⁠³. Wyoming rates by NAICS sector and has no plumbing line⁠⁴.

Base rates set by the state fund before experience modification. Ohio and Wyoming charge per $100 of payroll; Washington charges per hour worked, and part is withheld from wages. Other states’ insurers file their own rates; see where rates are published.

What the rows show (our calculations from the official 2026 files):

• Ohio. At $1.4612 per $100 of payroll, plumbing ranks 228th of the 501 classes in the July 1, 2026 schedule. It sits just above the median rate of $1.3390. It costs 1.34 times electrical wiring within buildings (5190, $1.0889) and 31 times clerical work (8810, $0.0466). Roofing (5551) costs 3.9 times as much⁠¹. Sewer construction is a separate class (6306, $1.7545). A firm that digs and lays sewer lines as well as working inside buildings has two classes to keep apart on its payroll records.
• Washington. Class 0306 costs $1.8222 for every hour worked in 2026 and ranks 108th of 320 classes. Of that, $0.3129 an hour is the worker’s share, which may be deducted from wages⁠³. Sewer and septic work (0108) is rated higher, at $2.2207. Electrical wiring (0601) is lower, at $1.4370. The hourly basis means a journey-level plumber and a trainee cost the same to insure per hour.
• Wyoming. Plumbers fall in 238000, Specialty Trade Contractors, at $2.39 per $100 in 2026⁠⁴. Construction is extrahazardous employment under Wyoming law, so coverage is compulsory, and the state fund is the only seller⁠²⁴⁠⁴. Because the class pools plumbers with roofers and every other trade, a Wyoming plumber pays more per $100 of payroll than an Ohio plumber, even though Ohio’s schedule has 501 classes to Wyoming’s 127.

In most other states, private insurers or competitive state funds set rates on top of bureau loss costs. The 5183 code still applies in NCCI-based states, but the price per $100 differs by insurer. See the class code guide and where official rates are published.

The BLS has no plumbing-only figure. Its June 2026 survey put construction employers’ comp cost at $1.10 per hour worked (2.1% of total compensation), against $0.43 for all private industry⁠⁵. The construction average mixes plumbers with higher-rated trades such as roofing (Ohio $5.7709, Washington $5.793)⁠¹⁠³. A plumbing-only firm may therefore come in below it, but no official figure confirms that.

Average employer cost per employee hour worked for workers' compensation and for health insurance, averaged across all workers in the group, plus workers' compensation as a percent of total compensation. Group averages mix high- and low-risk jobs, so they are not a premium rate for any single business. U.S. Bureau of Labor Statistics (BLS), National Compensation Survey, June 2026 (2026 Q2), private industry workers, released 9 Sep 2026.

Three plumbing payrolls priced at official rates

These are our calculations with stated assumptions, using official 2026 rates. They are not quotes. Each starts from the same idea: the premium is exposure times rate, adjusted by your own loss record.

1. Ohio, $400,000 of plumbing payroll

   $400,000 ÷ 100 × $1.4612 = $5,844.80 a year at the base rate⁠¹. An employer whose expected losses reach the minimum set in an appendix to rule 4123-17-05.1 is experience-rated and pays the base rate times its experience modification⁠². With a 1.15 mod the payroll costs $6,721.52; with a 0.85 mod, $4,968.08.

2. Washington, four plumbers at 2,000 hours each

   8,000 hours × $1.8222 = $14,577.60. The worker share is 8,000 × $0.3129 = $2,503.20, which leaves the employer about $12,074.40⁠³.

3. Wyoming, the same $400,000 payroll

   $400,000 ÷ 100 × $2.39 = $9,560 before the employer’s experience factor⁠⁴.

The Wyoming result is 64% higher than Ohio’s for identical payroll. That gap comes from how the classes are drawn, not from plumbing being riskier in Wyoming. Washington’s result can’t be compared directly, because it depends on hours, not wages.

Two practical points follow. First, office staff, dispatchers and estimators who never go to job sites belong in the clerical class, not in 5183 or 0306. The rate gap is 31 to 1 in Ohio and 8 to 1 in Washington⁠¹⁠³. Second, a premium audit after the policy year checks that split, so the records have to support it. See premium audits and the experience modification rate guide.

What a plumbing license requires you to carry

Plumbers are licensed twice in many states: the individual’s trade license and the business’s contractor license or registration. Insurance and bond conditions usually attach to the second. These are the rules we confirmed at the boards and in the statutes on October 13, 2026:

Scroll the table sideways to see every column.

The details that change what you buy:

• Texas. The insurance attaches to the license that pulls permits. A “responsible master plumber” is the master plumber whose license one plumbing company uses to offer work and obtain permits, and who has a certificate of insurance on file⁠⁶. The policy must be commercial general liability, written by an insurer authorized in Texas or an eligible surplus lines insurer. It must cover bodily injury and property damage “regardless of whether the claim arises from negligence or on a contract”, and provide at least $300,000 for all claims in a one-year period⁠⁶. A city or other political subdivision that requires the responsible master plumber to obtain a permit must verify with the board that the certificate is on file⁠⁶. The board’s form adds two conditions. The coverage must include every type of plumbing done under the license, including liquefied petroleum gas, medical gas and residential fire sprinkler plumbing where these apply. The certificate also expires when the policy does⁠⁷. A policy that excludes gas work therefore doesn’t meet the requirement for a company that does gas piping. Comp is optional for most Texas private employers. On a public building or construction contract, though, the contractor must certify comp coverage for every employee on the project, and so must each subcontractor⁠⁸.
• Florida. Every plumbing contractor certified or registered by the Construction Industry Licensing Board signs an affidavit at issuance and renewal saying it holds and will keep $100,000 of public liability and $25,000 of property damage cover. The board audits licensees at random by zip code⁠⁹. A general contractor’s minimum is $300,000 and $50,000⁠⁹. Florida covers construction employers from the first employee, and only up to three corporate officers who each own at least 10% may opt out⁠¹⁰.
• Washington. Two layers apply. Each person doing plumbing work needs a state certificate, temporary permit or trainee certificate, and must carry it on the job⁠¹⁸. The business must register as a contractor, which requires the $15,000 specialty bond and the liability limits in the table⁠¹⁷.
• California. Section 7125 lets most licensees without employees file a comp exemption. CSLB’s list of classifications that must carry comp regardless covers concrete, HVAC, asbestos abatement, roofing and tree service, but not plumbing⁠¹⁵. The exemption is also unavailable if the license is qualified by a Responsible Managing Employee⁠¹⁵. The $25,000 contractor bond applies to every license⁠¹⁶.
• Massachusetts. Any corporation, LLC or partnership with plumbing employees needs a plumbing business license. For a corporation, the applicant must be a master plumber who is a listed officer⁠¹¹. The board’s rules set no liability minimum. A local inspector can refuse a plumbing permit, however, if the licensee has not shown evidence of workers’ comp where chapter 152 requires it⁠¹¹. The statute also bars state and local agencies from issuing or renewing a business license or building permit without that proof⁠¹².
• Arizona. The Registrar of Contractors licenses plumbing as C-37 (commercial), R-37 (residential, including solar) or CR-37 (dual)⁠¹⁴. The bond depends on volume. A specialty commercial license with under $150,000 of annual work posts $2,500. One with $10 million or more posts between $37,500 and $50,000. Specialty residential bonds run from $1,000 to $7,500⁠¹³. Residential and dual licensees must also either post a further $200,000 bond or pay into the residential contractors’ recovery fund⁠¹³.

The state hubs for Texas, Florida, Washington, California, Massachusetts and Arizona cover each state’s wider comp system. The workers’ comp requirements table gives the employee threshold in all 51 jurisdictions.

How plumber liability is priced

Plumbing liability claims come from what happens inside a customer’s building: escaping water, gas, scalds, and damage done while cutting into walls and floors. No official source publishes claim frequency or average claim size for plumbers, so the useful facts are how the policy is rated and what the licensing rules demand.

• Payroll is the base. In ISO’s general liability program, “payroll is the ISO General Liability premium base for most contracting and service risks”⁠¹⁹. When Verisk introduced its size-of-risk rating supplement in 2021, it used plumbers as its example: “a plumber with a payroll of $2 million will have a lower loss cost per unit of exposure than a plumber with a payroll of $500,000”⁠¹⁹. Insurers that use the supplement can reflect that in the rate. A larger shop’s GL premium therefore rises with payroll, but more slowly than payroll does.
• Scope of work. Texas requires cover for every kind of plumbing the license is used for, including gas and medical gas⁠⁷. Gas lines, medical gas in clinics and fire sprinklers are different exposures from residential service calls. Tell each insurer what share of revenue comes from each, and check that the quote has no exclusion for work you actually do.
• Property damage limits. Florida’s $25,000 property damage minimum and Washington’s $50,000 are licensing floors⁠⁹⁠¹⁷. They say nothing about what a water loss in a finished home or a multi-tenant building can cost, and a general contractor or property manager hiring you can set higher limits by contract.
• Contract and negligence claims. The Texas statute requires the policy to respond to claims arising on a contract as well as from negligence⁠⁶. Contracts often require additional-insured status and specific limits. See the general liability guide for how those endorsements and limits affect the premium.

What insurers publish, and what they don’t

None of the insurer and broker pages in our data gives a figure for plumbers. These are the nearest published figures, all for other construction trades:

Insurer- and broker-reported figures from each company’s own customers, as published on its website; not a random sample of all businesses. Figures are rounded as published.

How to read them:

• ERGO NEXT general liability. These are averages for its own active U.S. customers who bought general liability in the previous 12 months (data updated April 2026): $95 a month for handymen, $120 for electricians and $210 for general contractors⁠²⁰. A plumbing firm is in none of these groups, and the company does not say where plumbers would fall.
• ERGO NEXT workers’ comp. $160 a month for construction customers. The sample note on that page describes commercial property buyers, which looks like a copy error⁠²¹. A one-person plumbing shop and a 20-plumber commercial contractor both sit inside that average.
• Progressive Commercial auto. A 2025 median of $203 a month and an average of $260 per vehicle for contractors, covering new policies with no driver violations⁠²².

All three describe each company’s own customers, mostly small businesses buying directly. None of them is a national average.

Service vans, tools and contract bonds

• Vans. Commercial auto is priced per vehicle and driver. Progressive’s contractor figures above are per vehicle⁠²². The commercial auto guide covers the rating factors, and state minimums set the lowest limits a van can legally carry.
• Tools, equipment and stock. General liability covers damage to other people’s property, not your own. Pipe threaders, drain cameras, jetters and parts carried in the van need their own cover, usually an equipment floater; see inland marine.
• License bonds. The bonds in the table above protect the public and the state, not the plumber. Washington’s and California’s are flat amounts; Arizona’s scale with your declared annual volume⁠¹³⁠¹⁶⁠¹⁷. None of the official sources here publishes bond premium rates; each surety sets its own.
• Contract bonds. Federal construction contracts over $150,000 require performance and payment bonds. Contracts from $35,000 to $150,000 need other payment protections⁠²³. A plumbing contractor bidding on public work needs bonding capacity as well as insurance; see surety bonds.

Building the figure yourself

No source gives a total insurance cost for a plumbing business, and none can be stated honestly without your payroll, state, vehicles and loss history. A method you can check against quotes:

1. Sort payroll by class

   Field plumbers, any sewer or underground crew, and office staff. In Washington, record hours instead of wages.

2. Price comp at the official or filed rate

   In Ohio, Washington and Wyoming, use the rates above. Elsewhere, ask the insurer for the class code, rate and loss-cost multiplier it used, then apply your experience mod. The workers’ comp estimator does the arithmetic with official rates.

3. Set liability limits from the strictest rule that applies

   Start with your state license minimum, then raise it to the highest limit your contracts require. Make sure gas, medical gas or sprinkler work is not excluded if you do it.

4. Compare GL quotes on the same base

   Ask each insurer which class and payroll figure it used, so the year-end audit doesn’t reprice the policy.

5. Add vans, equipment and bonds one by one

   Each has its own exposure base: vehicles and drivers, equipment values, and bond amount and credit.

The premium calculation guide explains each step in more detail.

Sources

1. 1
   Ohio Bureau of Workers' Compensation / Ohio Administrative Code, OAC 4123-17-06, Appendix A: base rates effective July 1, 2026 (private employers) Checked 13 Oct 2026 · Back to text ↑
2. 2
   Ohio Bureau of Workers' Compensation / Ohio Administrative Code, OAC 4123-17-03, Experience rating Checked 13 Oct 2026 · Back to text ↑
3. 3
   Washington State Department of Labor & Industries, 2026 hourly rates by risk classification Checked 13 Oct 2026 · Back to text ↑
4. 4
   Wyoming Department of Workforce Services, Workers' compensation 2026 industry base rates by classification Checked 13 Oct 2026 · Back to text ↑
5. 5
   U.S. Bureau of Labor Statistics, Employer Costs for Employee Compensation, June 2026 (released Sept. 9, 2026) Checked 13 Oct 2026 · Back to text ↑
6. 6
   Texas Legislature, Texas Occupations Code chapter 1301, Plumbers (sections 1301.002, 1301.3576, 1301.552) Checked 13 Oct 2026 · Back to text ↑
7. 7
   Texas State Board of Plumbing Examiners, Certificate of Insurance (COI) for a Responsible Master Plumber (revised August 2025) Checked 13 Oct 2026 · Back to text ↑
8. 8
   Texas Legislature, Texas Labor Code chapter 406, Workers' compensation insurance coverage Checked 13 Oct 2026 · Back to text ↑
9. 9
   Florida Construction Industry Licensing Board, Rule 61G4-15.003, Public liability insurance Checked 13 Oct 2026 · Back to text ↑
10. 10
    Florida Legislature, Florida Statutes 440.02, Definitions Checked 13 Oct 2026 · Back to text ↑
11. 11
    Massachusetts Board of State Examiners of Plumbers and Gas Fitters, 248 CMR 3.00, General provisions governing the conduct of plumbing and gas fitting work (Mass. Register 1559, Oct. 24, 2025) Checked 13 Oct 2026 · Back to text ↑
12. 12
    Massachusetts Legislature, General Laws chapter 152, section 25C Checked 13 Oct 2026 · Back to text ↑
13. 13
    Arizona Legislature, A.R.S. 32-1152, Surety bonds; cash deposits Checked 13 Oct 2026 · Back to text ↑
14. 14
    Arizona Registrar of Contractors, License classifications Checked 13 Oct 2026 · Back to text ↑
15. 15
    Contractors State License Board (CSLB), Workers' compensation requirements Checked 13 Oct 2026 · Back to text ↑
16. 16
    Contractors State License Board (CSLB), Bond requirements Checked 13 Oct 2026 · Back to text ↑
17. 17
    Washington State Department of Labor & Industries, Register as a contractor Checked 13 Oct 2026 · Back to text ↑
18. 18
    Washington State Legislature, RCW 18.106.020, Certificate or permit required Checked 13 Oct 2026 · Back to text ↑
19. 19
    Verisk (ISO), Here's a powerful new pricing tool for general liability insurers (Sept. 29, 2021) Checked 13 Oct 2026 · Back to text ↑
20. 20
    ERGO NEXT, How much does general liability insurance cost? (data updated April 2026) Checked 13 Oct 2026 · Back to text ↑
21. 21
    ERGO NEXT, How much does workers' comp insurance cost? (data updated April 2026) Checked 13 Oct 2026 · Back to text ↑
22. 22
    Progressive Commercial, Commercial auto insurance cost Checked 13 Oct 2026 · Back to text ↑
23. 23
    Acquisition.gov (General Services Administration), FAR 28.102-1, Performance and payment bonds: general Checked 13 Oct 2026 · Back to text ↑
24. 24
    Wyoming Legislature, Wyoming Statutes title 27, W.S. 27-14-108 (extrahazardous employment) Checked 13 Oct 2026 · Back to text ↑

Spotted an outdated figure? Report an error