Plumber insurance: coverage, requirements and costs

Why plumbers need business insurance

Plumbers get sued for water. A fitting that weeps behind a finished wall, a water heater that lets go in a closet, or a drain machine that pushes sewage into a basement produces a claim far larger than the invoice. Most of those losses surface months after you leave, so the policy has to respond to completed work as well as to what happens on the job.

The trade is also hard on the people doing it. The Bureau of Labor Statistics counted 75 fatal work injuries in plumbing, heating and air-conditioning contractors (NAICS 23822) in 2024 (BLS Table A-1), and its 2024 total recordable case rate for that group was 3.0 per 100 full-time workers, against 2.2 for construction as a whole (BLS Table 1). Trenching, ladders, crawlspaces, lifting and burns drive the claims, which is why workers' compensation is usually the largest premium line.

NAICS 238220 covers plumbing, heating and air-conditioning contractors, and the Census index also files sewer hookup and connection, fire sprinkler and lawn sprinkler installation there (NAICS 2022 manual). Tell your broker if you do any of that work; it changes the rating and sometimes the carrier.

Core coverages

• General liability. The commercial general liability policy pays for bodily injury and property damage you cause to others, including losses that appear after the job through completed operations coverage. It does not pay to redo your own faulty work, and in the standard ISO form that exclusion sits beside the one for the part of the property you were working on. The coverage you are buying is for resulting damage: the flooded floor, not the cracked fitting. See general liability insurance: what it covers and what it does not.
• Workers' compensation and employers liability. Statutory benefits, rated on payroll under NCCI class 5183 (plumbing not otherwise classified) in most states; California uses its own classes. Your experience modification rate adjusts the premium. See workers' comp class codes and why they matter.
• Commercial auto. Service vans carry parts, fuel and tools. Personal auto policies often limit business use, so confirm.
• Tools and equipment. Pipe machines, jetters and pressing tools are theft targets. Published limits on small-business programs can be thin: NEXT's plumber page shows tools and equipment limits of $3,000, $5,000 and $10,000 per occurrence by tier (NEXT). Compare that with the replacement value of one loaded van, and see contractor's equipment insurance: covering tools, machinery and rentals.
• Contractor errors and omissions. Covers financial loss from a design or installation error that does not involve injury or property damage. Ask about rip-and-tear, which pays to open and restore walls and floors to reach a defect.
• Umbrella. General contractors and commercial customers often require an umbrella on top of $1 million primary limits (umbrella policy).

Coverage you may be required to carry

State licensing. Many states license plumbers, and some tie the license to insurance. In Texas, a responsible master plumber must have a certificate of insurance on file with the State Board of Plumbing Examiners showing commercial general liability of not less than $300,000 for all claims in a one-year period, and cities that issue plumbing permits must confirm it (Tex. Occ. Code 1301.552; TSBPE). California requires a $25,000 contractor license bond for the plumbing classification like every other trade (CSLB). Washington requires a $15,000 bond for specialty contractors (RCW 18.27.040), and its workers' compensation comes from the state fund. Use workers' comp and benefits requirements by state for the comp rules in your state.

Workers' compensation. Required by state law once you have employees; thresholds, and whether a sole proprietor can opt out, vary by state.

General contractors and owners. When you work as a subcontractor, expect a contract asking for general liability of $1 million per occurrence and $2 million aggregate, CG 20 10 and CG 20 37 additional insured wording, waiver of subrogation, primary and noncontributory status and umbrella limits. Public owners such as Indiana University and UNLV publish this pattern for prime contractors, and primes pass it down (Indiana University). Anti-indemnity laws in states such as Texas and New York limit how much of the prime's negligence you can be asked to absorb; see managing subcontractor insurance and certificates.

Common claims and how to prevent them

• Water damage. Pressure-test before closing walls, label and photograph shut-off locations, and leave a written note for the owner.
• Sewer and drain claims. Camera the line first so existing damage is documented. Ask how the policy treats sewage and mold; many liability policies restrict both.
• Burns and fire. OSHA's construction fire-prevention rule for welding and cutting requires extinguishers in the work area and a fire watch for a sufficient period after the work (29 CFR 1926.352). Move combustibles, use heat shields and keep a log.
• Trenches. Excavations that employees enter need a protective system unless they are in stable rock or under 5 feet deep with a competent person finding no sign of cave-in (29 CFR 1926.652). OSHA runs a National Emphasis Program on trenching and excavation (OSHA).
• Underground utilities. Locate before you dig. Contractors who dig often meet an XCU exclusion (explosion, collapse, underground property) that must be bought back.

What drives the cost

Workers' comp is payroll times the class rate, adjusted by the mod, and the audit uses what your employees actually did. General liability is rated on payroll or gross receipts by operation. Underwriters want the split between new construction and service and repair, residential and commercial, and the share of work that is drain cleaning, sewer line, gas piping, water heaters, backflow testing or medical gas. They also ask about subcontractors and whether you hold their certificates, your largest jobs, license status, years in business and loss history. Auto is rated on vans, drivers and radius; tools on scheduled value. See the workers' comp premium calculator.

Specialized coverages to consider

• Contractors pollution liability. The standard pollution exclusion removes most releases; see pollution liability insurance and the pollution exclusion.
• Higher liability limits and excess. Large commercial customers set the floor.
• Rip-and-tear and defective-work endorsements on contractor errors and omissions.
• Fire sprinkler, backflow and gas work. If you design or certify these, confirm the policy does not exclude them or treat them as professional services.

How to buy

Use an agent who places contractors, or an online carrier for a small shop, and compare endorsements rather than premium alone. NEXT Insurance lists plumbers among the trades it quotes online, with tiered general liability limits of $300,000 and $1 million per occurrence. Have ready: payroll by employee, a split of revenue by type of work, your largest jobs, subcontractor cost and certificates, license numbers, vehicle list and tool values.

Key takeaways

• Water damage is the claim to underwrite around; check how the policy treats sewage, mold and completed operations.
• Plumbing is an injury-heavy trade, so workers' comp and safety records, especially trenching, drive the price.
• Texas requires $300,000 of general liability for a responsible master plumber; other states differ, so check your board.
• Subcontract insurance requirements and anti-indemnity laws shape how much risk you carry.
• Tools, vans and underground work need their own limits and endorsements; confirm the XCU position.