How do I check if a plumber is licensed?
Search the plumber's license number at your state plumbing board — California uses C-36, Texas uses TSBPE (Texas State Board of Plumbing Examiners), Florida uses CFC (Certified Plumbing Contractor), Oregon uses LP (Licensed Plumber). Plumbing licensing is required in nearly every state, even where general contractor licensing is not.
Plumbing, like electrical, is licensed at the state level in nearly every US state — including states without statewide GC licensing. The reason: plumbing failures cause water damage, sewage backups, gas leaks, and code violations that can kill or seriously injure occupants.
State plumbing license boards:
- California: C-36 Plumbing Contractor (CSLB.ca.gov). - Texas: Texas State Board of Plumbing Examiners (TSBPE.state.tx.us). Issues Master Plumber, Journeyman, Tradesman, and Apprentice licenses. - Florida: CFC (Certified Plumbing Contractor) or RFC (Registered Plumbing Contractor) (myfloridalicense.com). - New York: licensed at city/county level (NYC DOB Master Plumber, Nassau County, etc.). - Illinois: licensed by the Illinois Department of Public Health (idph.illinois.gov/PlumbersLP/PlumbersLookup.aspx). - Oregon: Plumbing License through Building Codes Division (oregon.gov/bcd). - Washington: L&I Plumbing License (lni.wa.gov). - Arizona: C-37 Plumbing through ROC. - North Carolina: NC State Board of Examiners of Plumbing, Heating and Fire Sprinkler Contractors. - Massachusetts: Board of Registration of Plumbers and Gas Fitters.
Plumbing license classes:
- Master Plumber: full scope, can pull permits, can supervise. - Journeyman Plumber: works under master supervision. - Gas Fitter: specifically authorized for gas line work — sometimes a separate license, sometimes combined with plumbing. - Medical Gas: specialty for hospital and lab work.
What to verify:
1. License status Active. 2. License class authorizes the work. A residential-only license cannot do commercial work, and vice versa. 3. Gas-fitter authorization if any gas work is involved (water heater, range, fireplace, pool heater). In many states, gas work requires a separate endorsement. 4. Workers' comp current. Plumbers handle heavy equipment and have job-site injury risk.
Why gas work needs extra scrutiny: gas leaks kill. Carbon monoxide poisoning, explosion, and fire are all real risks from unlicensed gas work. Many states require a separate gas-fitter license and a CO/gas sniffer test at completion.
Plumbing-specific red flags:
- Plumber wants to skip permits for water heater replacement. Most jurisdictions require a permit for water heater replacement because it involves gas/electrical, and inspection ensures the T&P valve is correctly piped. - Plumber proposes PEX-A or PEX-B routing through prohibited areas (UV exposure, direct concrete contact in some areas). - Plumber proposes flex connector for water heater gas in violation of code. - Plumber proposes Polybutylene replacement that does not address the full system (PB is class-action material; partial replacement is a red flag).
Groundcheck (earthmove.io/trust) verifies plumbing licenses across all 51 jurisdictions. Run a separate Groundcheck on the GC and on the plumbing sub — different entities, different license requirements. Groundcheck does NOT verify gas-fitter endorsements specifically; check the state board's license detail page for endorsement status.
Run a free Groundcheck
Verify any contractor or business. License status, court records, OSHA history. Under 90 seconds. The business is never notified.