What licenses do you need to start a plumbing business?

Start with who licenses the trade where you will work, because the plumbing licence does not arrive in one standard wrapper.

In a first group of states, the licence belongs to the company.

Florida's Construction Industry Licensing Board issues a plumbing contractor licence that is unlimited in the plumbing trade and comes certified (statewide) or registered (local).

California's Contractors State License Board issues the C-36 Plumbing Contractor classification, covering a safe water supply of suitable volume and temperature and the proper disposal of fluid waste from the premises.

Ohio is the inverse edge: it has no individual plumber licence at all — as of September 2026, the state licenses plumbing contractors (businesses) only.

In a second group, the state issues no company licence to apply for: an individual master plumber's (or equivalent) licence is what lets a business contract.

That group changes your start-up sequence, so it gets its own section below.

In a third group, there is no state plumber licence at all: as of September 2026, plumbers are licensed by cities and counties (or an industry board) in Florida, Kansas, Missouri, Nebraska, Nevada, New York and Wyoming.

That finding is about the worker licence.

The business-side licence a contracting company needs in one of those states, where one is required, is a local question — the exact answer is that city's or county's to give, so start with the local licensing authority where you will work.

Florida shows why the layers do not move together: its contractor licence is certified statewide or registered locally, yet Florida is also one of the states with no state worker licence — individual plumbers there are licensed by cities and counties.

Sorting one layer does not settle the other.

Cities can own a business-registration layer of their own.

In New York City, the plumbing "contractor" licence is the Master Plumber licence itself: the applicant must be an officer, partner or sole proprietor of the business, and the business must keep a NYC place of business in a zoning-compliant (commercial) location.

Chicago stacks a city licence on top of the state one instead: a state-registered Illinois plumbing contractor must also get a City of Chicago plumbing contractor licence to work in the city — the applicant must be a Chicago-licensed plumber, and the business files a $20,000 performance bond with the City Clerk.

Which classifications, job-value thresholds and exam portions each state attaches to the company licence is a study of its own — our plumbing contractor license guide runs the full state-by-state rundown, board by board.

Forming your LLC or corporation is a separate track from the licence layers above.

Licensing is often local, and rules change.

Confirm the current requirement with the state board — or with the city or county where licensing is local — before you bid your first job.

The master licence sits at the top of the individual ladder — as of September 2026, 24 states run the classic apprentice or trainee → journeyman → master plumbing ladder — and in a large group of states that top individual licence is also what lets a business contract.

There is no separate state plumbing-contractor licence to apply for in Georgia, Maine, Kentucky, Delaware, Montana, Wisconsin, Texas, Louisiana, New Jersey, North Dakota, Connecticut and Rhode Island, and the same holds in New York City and under Nebraska's city master licences.

What that looks like in practice: a Texas business that advertises or offers plumbing must secure the services of a Responsible Master Plumber (RMP).

In Montana, only a licensed master plumber may plan, estimate, bid, contract for and supervise plumbing work — and only masters may pull plumbing permits — so the business designates a "master plumber of record" on a form filed with the board for a $50 fee.

Wisconsin issues licences to individuals only, never to firms, and plumbing may be installed only with a licensed master plumber in charge.

Connecticut shows why the word equivalent matters: it has no master title, so the credential a business contracts through is the individual P-1 Unlimited Plumbing Contractor licence.

And in a few states there is no master licence to staff at all: Connecticut, Idaho, Indiana, Oklahoma and South Dakota top out at an individual contractor licence instead of a master licence, while Alaska, New Mexico, Oregon and Washington license at the journey level with no state master (as of September 2026).

Ask the board in those states what the business layer requires before you plan around a title that does not exist there.

Where a company licence does exist, states such as Colorado and Massachusetts also require a named licensed individual standing behind it — the qualifier — and the title varies by state: Colorado's is the Responsible Master Plumber; Massachusetts', the master plumber of record.

Who may serve, whether one person can back two companies, and what you must file when that person leaves are consequential rules for a new shop: our guide to the license qualifier covers that machinery.

The individual ladder itself — apprentice, journeyman, master — is career-guide territory: start with what a master plumber is.

Two services come with credential maps of their own, and a new owner should price them into the plan from day one: gas piping and backflow testing.

The state credentials our research found for both are separate from the plumber licence; the states we did not document are the board's to answer, so ask before you advertise either service.

Gas fitting is licensed separately from plumbing in a long list of states.

Standalone state gas-fitter credentials, separate from the plumber licence, were found in Alabama, Alaska (Plumber Gas), Arkansas, DC, Louisiana, Maine (propane & natural gas technician), Maryland, Massachusetts, New Hampshire (fuel gas fitter), New Mexico (JG), North Carolina (fuel piping), Utah (natural gas technician), Vermont and Virginia — while Texas regulates LP-gas through the Railroad Commission (as of September 2026).

Propane adds its own layer: separate LP-gas credentials or regulators were found in Texas (Railroad Commission), Arkansas (LP Gas Board), Alabama (LP Gas Board), Maryland (Propane Gas Fitter), Massachusetts (LP installer), Vermont (LP Gas Installer), Maine (propane technician) and Virginia (LP gas fitter).

Texas is the worked example.

LP-gas (propane) work there is regulated by the Railroad Commission, not the plumbing board: each individual must pass an RRC exam for the activity they perform and must work for an RRC-licensed company.

Master or journeyman plumbers (TSBPE) may instead register with the RRC for an LP-gas exemption that lets them install and service LP-gas piping, containers and certain appliances without separate RRC certification, renewable at $20 a year — but the exemption covers only the named individual, so your employees cannot work under it.

Each tech on a propane job needs their own qualification.

Backflow testing runs on its own credential map too.

State-issued backflow tester credentials were found in Texas (a TCEQ Backflow Prevention Assembly Tester, or BPAT, licence), Arkansas (Assembly Testing Technician), Virginia (backflow prevention device worker), Wisconsin (Cross Connection Control Assembly Tester), Minnesota (testers need ASSE 5110) and Washington (the backflow PL30 plumber specialty requires a DOH tester certificate); Louisiana and Texas also offer licensed plumbers a "Water Supply Protection Specialist" endorsement.

In Texas, a BPAT licence is required of anyone who tests or repairs backflow prevention assemblies.

Our research documented tester credentials in the states above, but not every state's backflow rules — ask the board before you advertise the service.

Texas is where the add-on pattern becomes a hiring pattern: the Railroad Commission certifies individuals, the LP-gas exemption covers only the named individual, and the BPAT licence is required of anyone who tests or repairs backflow prevention assemblies — there, the add-on credential belongs to the tech who does the work, not only to the company.

The worker side is its own subject: see what a gas fitter does and the backflow tester career guide.

Run the layers in the order you will meet them.

First, identify the issuer: the state board, or — in the states whose worker licences are local — the city or county where you will work.

Second, settle the qualifier question: whether you will hold the master (or equivalent) licence the business stands on yourself, or employ someone who does, and what your board requires of that arrangement.

Third, file the company-side registration where your state issues one.

Fourth, list the add-on credentials for the services you plan to advertise — gas fitting, LP-gas, backflow testing.

Fifth, the bond and insurance step: what a board or city requires varies, and our research did not confirm amounts for every state — our guide to contractor license bonds and insurance collects the examples.

Finally, calendar every renewal: where the master licence is the contracting licence, keeping that individual credential current is what keeps the business legal.

The licence you hire against is a separate track.

Your future techs face the individual ladder, and what a hire needs is a different question from what the business needs — our guide to what license your hire needs separates the two.

Once the licensing stack is mapped, the growth side is people: our guide to hiring HVAC and plumbing techs covers sourcing, pay plans and screening.

This page is employer career and business information, not legal advice. Licensing requirements are set by each state's board — or by your city or county where licensing is local. Confirm every requirement above with the issuing body before you bid or advertise.