How to verify a plumber or HVAC contractor
Where to check a plumber's or heating and cooling contractor's license in each state, what to ask about insurance, and what a written quote should include.
Updated September 28, 2026
Most of what a plumber or heating and cooling contractor tells you can be checked before work starts. Here's where to look and what to ask.
Check the license
Ask for the license number and the name it's issued to, then look it up. The table links each state's lookups for plumbing and for heating and cooling, and says where licensing is local instead. Some lookups search people rather than businesses, so ask for the license holder's own name as well as the company's. Make sure the name on the license matches the business on your quote, or ask the contractor to explain how they're connected.
| State | Plumbing | Heating and cooling |
|---|---|---|
| Alabama | Alabama Plumbers and Gas Fitters Examining Board license lookup, with a business search one tab over | Alabama Board of Heating, Air Conditioning and Refrigeration Contractors license lookup |
| Alaska | Alaska Division of Corporations, Business and Professional Licensing registration lookup for the business. Journeyman plumbers hold certificates of fitness from the Department of Labor and Workforce Development,1 so ask to see one | Alaska Division of Corporations, Business and Professional Licensing registration lookup |
| Arizona | Arizona Registrar of Contractors license lookup | Arizona Registrar of Contractors license lookup |
| Arkansas | Arkansas Department of Health license lookup (individual licensees) | Arkansas Department of Labor and Licensing license lookup (search people by name and city) |
| California | Contractors State License Board license lookup, by license number | Contractors State License Board license lookup, by license number |
| Colorado | Colorado State Plumbing Board license lookup (choose Plumbers in the profession list) | Ask your city. Denver, for example, issues heating and ventilating contractor certificates2 |
| Connecticut | Connecticut eLicense license lookup (choose Plumbing and Piping as the license type) | Connecticut eLicense license lookup (choose Heating, Piping and Cooling, or Sheet Metal) |
| Delaware | Delaware Division of Professional Regulation license lookup (choose Individual or Facility first) | Delaware Division of Professional Regulation license lookup |
| District of Columbia | DC Department of Licensing and Consumer Protection license lookup | DC Department of Licensing and Consumer Protection license lookup |
| Florida | Florida Department of Business and Professional Regulation license lookup | Florida Department of Business and Professional Regulation license lookup |
| Georgia | Georgia Secretary of State license lookup | Georgia Secretary of State license lookup |
| Hawaii | Hawaii Professional and Vocational Licensing license lookup: a business by license number, or a person on the Business/Individual tab | Hawaii Professional and Vocational Licensing license lookup |
| Idaho | Idaho Division of Occupational and Professional Licenses license lookup (choose the plumbing board) | Idaho Division of Occupational and Professional Licenses license lookup (choose the HVAC board) |
| Illinois | Illinois Department of Public Health license lookup (current plumbers with an active license only) | Ask your city or county whether it licenses heating and cooling contractors |
| Indiana | Indiana Professional Licensing Agency license lookup (choose Plumbing Commission as the profession) | Ask your city or county whether it licenses heating and cooling contractors |
| Iowa | Iowa Department of Inspections, Appeals and Licensing license lookup (choose Plumbing and Mechanical Systems as the program) | Iowa Department of Inspections, Appeals and Licensing license lookup (choose Plumbing and Mechanical Systems as the program) |
| Kansas | Cities and counties set licensing for construction and contracting businesses.3 Ask your city or county | Cities and counties set licensing for construction and contracting businesses.3 Ask your city or county |
| Kentucky | Kentucky Department of Housing, Buildings and Construction license lookup (choose Division of Plumbing) | Kentucky Department of Housing, Buildings and Construction license lookup (choose Division of HVAC) |
| Louisiana | State Plumbing Board of Louisiana license lookup | Louisiana State Licensing Board for Contractors license lookup (current licensees only). A Mechanical license is required for air conditioning, refrigeration and heating work over $10,0004 |
| Maine | Maine Plumbers' Examining Board license lookup | Maine Fuel Board license lookup, for oil, propane and natural gas technicians. For air conditioning work, ask the contractor which licenses they hold |
| Maryland | Maryland State Board of Plumbing license lookup, active licenses only | Maryland HVACR board license lookup, active licenses only |
| Massachusetts | Massachusetts Division of Occupational Licensure license lookup | Sheet metal (ductwork) licenses: the Division of Occupational Licensure license lookup. Refrigeration technicians: the Office of Public Safety and Inspections license lookup |
| Michigan | Michigan LARA license lookup (choose Plumbing Contractor as the license type) | Michigan LARA license lookup (choose Mechanical Contractor) |
| Minnesota | Minnesota Department of Labor and Industry license lookup (choose Continue as Guest, then Search License/Registration Holders) | There's no state license, but mechanical contractors must file a $25,000 bond with the Department of Labor and Industry, and cities may require licenses or competency cards.5 Ask your city |
| Mississippi | Mississippi State Board of Contractors license lookup | Mississippi State Board of Contractors license lookup |
| Missouri | There's no state plumbing license. State law sets plumber qualifications for the larger cities and counties that license locally.6 Ask your city or county | Ask your city or county whether it licenses heating and cooling contractors |
| Montana | Montana Department of Labor and Industry license lookup (choose Board of Plumbers) | Ask your city or county whether it licenses heating and cooling contractors |
| Nebraska | Cities license master and journeyman plumbers, and all contractors register with the Nebraska Department of Labor.7, 8 Ask your city | The state's contractor registration isn't a competency license.8 Ask your city |
| Nevada | Nevada State Contractors Board license lookup | Nevada State Contractors Board license lookup |
| New Hampshire | New Hampshire Office of Professional Licensure and Certification license lookup (choose Mechanical as the profession) | Fuel gas fitters are licensed,9 and the same license lookup covers them. For air conditioning work, ask the contractor which licenses they hold |
| New Jersey | New Jersey Division of Consumer Affairs license lookup (choose Person Search, then Master Plumbers) | New Jersey Division of Consumer Affairs license lookup (choose Person Search, then HVACR) |
| New Mexico | New Mexico Construction Industries Division license lookup. The state's licensing department links to it. PSI runs the page, and it doesn't carry New Mexico branding | New Mexico Construction Industries Division license lookup |
| New York | There's no state plumbing license. Cities such as New York City and Rochester license plumbers.10, 11 Ask your city or county | Licensing is local where it exists, such as New York City's oil burner installer licenses.12 Ask your city or county |
| North Carolina | North Carolina Board of Examiners of Plumbing, Heating and Fire Sprinkler Contractors license lookup (filter by a plumbing classification) | North Carolina Board of Examiners of Plumbing, Heating and Fire Sprinkler Contractors license lookup (filter by a heating classification) |
| North Dakota | North Dakota State Plumbing Board license lookup. Jobs over $4,000 also need a Secretary of State contractor license:13 North Dakota Secretary of State license lookup, searched by name | Cities issue master and journeyman HVAC licenses after a statewide exam,14 and jobs over $4,000 also need a Secretary of State contractor license.13 Ask your city |
| Ohio | Ohio Construction Industry Licensing Board license lookup (choose PL, Plumbing Contractors). The state license covers commercial work, and residential licensing is local,15 so for work on a home, ask your city too | Ohio Construction Industry Licensing Board license lookup (choose HV, HVAC Contractors). For work on a home, ask your city too |
| Oklahoma | Oklahoma Construction Industries Board license lookup | Oklahoma Construction Industries Board license lookup |
| Oregon | The business holds a Building Codes Division plumbing contractor license and a Construction Contractors Board license.16 Check both: the Building Codes Division license lookup and the Construction Contractors Board license lookup | Construction Contractors Board license lookup |
| Pennsylvania | There's no state plumbing license. Some municipalities license plumbers, and home improvement contractors register with the Attorney General.17, 18 Ask your municipality | Home improvement contractors register with the Attorney General.19 Ask your municipality about licensing |
| Rhode Island | Rhode Island Department of Labor and Training license lookup (choose Plumber as the trade) | Rhode Island Department of Labor and Training license lookup (choose Mechanical as the trade) |
| South Carolina | Commercial plumbing over $10,000 needs a mechanical contractor license with the plumbing classification.20 Check the Contractor's Licensing Board license lookup and the Residential Builders Commission license lookup | Contractor's Licensing Board license lookup |
| South Dakota | South Dakota Plumbing Commission roster (a PDF list grouped by city) | Ask your city or county whether it licenses heating and cooling contractors |
| Tennessee | Tennessee Board for Licensing Contractors license lookup. Plumbing jobs of $25,000 or more need a contractor license, and smaller jobs need a Limited Licensed Plumber license where the state permits and inspects. Larger cities license plumbers locally21, 22 | Tennessee Board for Licensing Contractors license lookup |
| Texas | Texas State Board of Plumbing Examiners license lookup (choose a search type first) | Texas Department of Licensing and Regulation license lookup (choose Air Conditioning Contractors), active licenses only |
| Utah | Utah Division of Professional Licensing license lookup | Utah Division of Professional Licensing license lookup |
| Vermont | Vermont Division of Fire Safety roster of licensed plumbers | The Division of Fire Safety issues oil burner installer licenses, gas certifications and a refrigeration and air conditioning electrical specialist license.23 Its roster of every active license it issues covers them. For other work, ask the contractor which licenses they hold |
| Virginia | Virginia Department of Professional and Occupational Regulation license lookup (it may ask you to pass a check first) | Virginia Department of Professional and Occupational Regulation license lookup |
| Washington | Washington Department of Labor and Industries registration lookup (choose how to search in the Search by list first) | Washington Department of Labor and Industries registration lookup |
| West Virginia | West Virginia Division of Labor plumber license lookup for the plumber. The business needs a contractor license with the plumbing classification for residential jobs of $5,000 or more and commercial jobs of $25,000 or more:24, 25 West Virginia Contractor Licensing Board license lookup. The Division of Labor's page isn't a secure (https) page, so your browser may warn you | West Virginia Division of Labor HVAC license lookup (also not a secure page) |
| Wisconsin | Wisconsin Department of Safety and Professional Services license lookup | Wisconsin Department of Safety and Professional Services license lookup |
| Wyoming | There's no state plumbing license. Cities such as Casper and Cheyenne license plumbing contractors and plumbers.26, 27, 28 Ask your city | Ask your city or county whether it licenses heating and cooling contractors |
If a license doesn't show up, check the spelling and try the license number, then ask the contractor. Some lookups list active licenses only.
Ask about insurance
Ask for a certificate of insurance showing general liability and workers' compensation, and ask for it to name you. Then call the insurer or agent on the certificate and ask whether the policy is active and covers the work you're hiring for.
If the contractor says they don't need workers' compensation, ask why, and ask who pays if someone is hurt on your property.
Get the quote in writing
Ask each contractor for a written quote that says:
- What they'll do, and the make, model and size of any equipment they'll install.
- Whether the price is fixed or hourly, and what would change it.
- Whether removing the old equipment, the permit, the inspection and cleanup are included.
- Who applies for any permit. The permit guide covers water heater, furnace and AC swaps.
- What the warranty covers, on the equipment and on the labor, and for how long.
- How much of a deposit they want, and when the rest is due.
Compare quotes line by line, and ask for anything missing to be priced. The cost guides for plumbers, water heaters, sewer lines, air conditioners and heat pumps and furnaces show published ranges for common jobs.
When you're ready, you can ask for quotes from contractors near you.
License lookups and licensing rules from state licensing boards, agencies and legislatures, and city governments, checked September 2026.
Sources (28)
- Alaska Department of Labor and Workforce Development: plumbing and electrical ↑
- Denver Community Planning and Development: mechanical certificates ↑
- Kansas Business Center: construction ↑
- Louisiana State Licensing Board for Contractors: blue book ↑
- Minnesota Department of Labor and Industry: mechanical contractor bond ↑
- Revisor of Missouri: RSMo 341.010 ↑
- Nebraska Legislature: section 18-1901 ↑
- Nebraska Department of Labor: contractor registration ↑
- New Hampshire rules: Saf-Mec 300 ↑
- New York State Senate: General City Law article 4 ↑
- City of Rochester: examining board of plumbers ↑
- NYC Open Data: DOB license info ↑
- North Dakota Secretary of State: contractor licensing ↑
- City of Fargo: HVAC exams ↑
- Ohio Department of Commerce: OCILB contractors ↑
- Oregon Building Codes Division: contractor licenses ↑
- Pennsylvania Department of Labor and Industry: contractor licensing ↑
- City of Philadelphia: master plumber license ↑
- Pennsylvania Attorney General: home improvement contractor registration ↑
- S.C. Code title 40, chapter 11 ↑
- Tennessee Board for Licensing Contractors: classifications ↑
- Tennessee Board for Licensing Contractors: Limited Licensed Plumber ↑
- Vermont Division of Fire Safety: licensing ↑
- W. Va. Code 30-42-3 ↑
- West Virginia Secretary of State: legislative rule ↑
- Wyoming State Fire Marshal: licensing ↑
- City of Casper: contractor licensing ↑
- City of Cheyenne: Contractor Licensing Board ↑