Plumber Licensing by State: How to Verify a License

Plumber Licensing by State: How Verification Actually Works

"Licensed plumber" is the most used and least examined phrase in home services. There is no national plumber license and no single register. Each state decides who licenses plumbers, some states license them centrally, some leave it to cities and counties, and a few do both in layers, and the license classes (apprentice, journeyman, master, contractor) mean slightly different things in each system. This guide explains the models, then gives, for every state this directory lists businesses in, the authority that licenses plumbers and where its official register lives. It is general information about how licensing works, checked against the authorities' own publications in November 2026; it is not legal advice, and the authority's own site governs if anything here and there differ. For the state pages with local detail, follow the state links at the end of each row: every state in this table has a licensing page on this directory under /plumbing-licenses/.

The Three Models

State licensing. A state board or agency issues the plumber or plumbing contractor license and keeps a public register. Texas (State Board of Plumbing Examiners), California (Contractors State License Board, classification C-36 Plumbing), Arizona (Registrar of Contractors), Florida (Department of Business and Professional Regulation), Washington (Department of Labor and Industries), Colorado (Department of Regulatory Agencies), Minnesota (Department of Labor and Industry), Maryland (State Board of Plumbing), Michigan (Department of Licensing and Regulatory Affairs), Massachusetts (Board of State Examiners of Plumbers and Gas Fitters), Georgia (State Construction Industry Licensing Board, Division of Plumbers, administered through the Secretary of State), Illinois (Department of Public Health, under the state Plumbing License Law), and North Carolina (State Board of Examiners of Plumbing, Heating and Fire Sprinkler Contractors) all license plumbers at the state level, though most also require local permits for the work itself.

Local licensing. New York and Missouri do not issue a statewide plumber license. In New York, cities and counties license plumbers; New York City licenses Master Plumbers through its Department of Buildings, and permits there run through that system. In Missouri, licensing is handled by city and county boards of examiners, including in St. Louis, and there is no state register to search.

Layered systems. Pennsylvania has no state plumber license either; instead the state requires home improvement contractors to register with the Attorney General under the Home Improvement Consumer Protection Act, while cities such as Philadelphia and Pittsburgh run their own trade licensing. Ohio licenses plumbing contractors at the state level through the Ohio Construction Industry Licensing Board for commercial work, while residential work is commonly governed by city or county registration and licensing. In layered states, the right question is never just "are you licensed" but "licensed or registered by whom, for this kind of work, in this city."

How To Verify, in Four Moves

First, ask the business for its license number and the exact name the license is issued to; legitimate businesses print it on quotes, invoices, and often the truck. Second, search the official register for your state from the table below, by number where you can, and confirm four fields: the name matches the business you are hiring, the classification covers your type of work, the status is active, and the expiration date is in the future. Third, read what the register shows beyond status: several registers publish bond and insurance filings (California's CSLB record shows bond and workers compensation status; Arizona's ROC search shows classification and complaint history) and disciplinary actions (Texas's public search shows them). Fourth, insurance is a separate check from licensure: ask for a certificate of insurance and confirm it the way How We Verify describes for this directory's Verified badge.

Two cautions belong with the method. A register proves a license exists and is current; it does not rate workmanship, and this directory's own listings are compiled from public records and are labelled Unclaimed until a business joins and, for the Verified badge, passes license and insurance checks. And a license in one state never authorizes work in another; in local-licensing states, it may not even authorize work in the next city.

The States This Directory Covers

Texas, in Detail, Because This Directory Is Wired To It

Texas deserves a paragraph of its own here for a practical reason: it is the licensing system this directory's verification process connects to most directly. Texas plumbing businesses operate under a Responsible Master Plumber (RMP), whose license number appears on the company's advertising and invoices. The TSBPE Public License Search shows license class, status, expiration, insurance certificate status, and disciplinary actions in the same record. Before hiring in Texas, get the RMP's number, search it, and confirm the record is active with insurance on file. The license classes you will see, apprentice, tradesman, journeyman, master, and responsible master, describe who may do and who may be responsible for the work, and How to Choose a Plumber explains how to use that ladder in an interview.

What a Directory Badge Is, and Is Not

This directory's Verified badge means the business claimed its listing and passed the license and insurance checks described on How We Verify, re-checked as described there. It is a directory check, performed against the registers above, and it is not a license, an endorsement by any board, or a guarantee of work. Most listings on this site are unclaimed public records with no badge, and they are labelled that way. Whether or not you hire through this directory, the four verification moves above, done against the official register for your state, are the strongest ten minutes you can spend before plumbing work starts. Start from your metro's board on the directory home page, read How Rankings Work for how listings are ordered, and when you are ready, get matched free.

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Expert Reviewed: Reviewed by the Directory of Plumbers editorial team against the licensing authorities' publications, November 2026. General information only, not legal advice. Licensing rules change; the issuing authority's own register is the governing source.