How Do You Get a Plumbing License in New Hampshire?

Yes.

New Hampshire licenses plumbers statewide through the OPLC Mechanical Licensing Board under RSA 153:27-38, at three levels: apprentice, journeyman and master plumber.

If you find older material citing RSA 329-A, that law was repealed effective July 1, 2013, and plumbing licensure now sits in RSA 153:27-38.

The requirement also has boundaries the statute draws: it does not apply to plumbing done in connection with installing heating, cooling, air-conditioning or domestic water-heating systems (solar, oil, gas or electric), or to water treatment and pool work, although code, permit and inspection rules still apply.

The board licenses three individual levels: apprentice plumber, journeyman plumber and master plumber.

A journeyman plumber customarily performs the work of installing, maintaining and repairing plumbing and drainage under the direction of a master plumber, and in New Hampshire law a master plumber is the person or business that employs plumbers or does plumbing as a business.

There is no separate plumbing contractor license class: a plumbing business licenses through a Mechanical Business Entity license with a New Hampshire master plumber as its officer or responsible managing employee.

The state's legal definition of plumbing stops at the first fitting beyond the foundation wall or 5 feet of pipe from the building, and the board also certifies water treatment technicians separately.

The apprentice license is the entry point: every New Hampshire plumbing apprentice must hold a Mechanical Licensing Board apprentice license or ID card, and the application must include an apprenticeship agreement signed by the Department of Labor.

The apprenticeship that agreement covers is 8,000 hours of on-the-job training plus 144 hours of related classroom instruction per year.

For the journeyman license, the rule for in-state applicants asks for an apprenticeship completion certificate, at least 600 hours of plumbing education and at least 8,000 hours of on-the-job plumbing experience; whether an exam is also required on that in-state route was not settled by the board pages we read, so confirm with OPLC before you apply.

A master applicant must have held a New Hampshire journeyman license for at least 6 months.

As of September 2026 the fees are $88 for an apprentice, $198 for a journeyman and $330 for a master, charged at application and again at each renewal.

An apprentice ID card also renews every 2 years, and only while the apprentice remains enrolled in the apprenticeship and trade-related education.

Since May 12, 2025, the New Hampshire plumbing examination has been proctored by ProV (Professional Credential Verification).

The board's rules set the pass marks: a journeyman licensed in another state qualifies by passing the New Hampshire journeyman exam with at least 70%, and a master applicant must pass the master exam with at least 75%.

Our research did not capture the exam's code edition or whether it is open book, so read the candidate information ProV and OPLC publish before you schedule.

For study context, New Hampshire updated its adopted mechanical and plumbing codes to the 2021 editions effective July 1, 2024; which edition the exam tests was not captured in our research.

New Hampshire's individual mechanical licenses, including the journeyman and master plumber licenses, expire every 2 years on the last day of the month they were issued.

Each 2-year cycle, individual mechanical licensees must complete no fewer than 6 hours of board-approved continuing education for each plumbing endorsement; OPLC describes that as 3 hours of code update each year.

Renewal costs the same as application: $88 apprentice, $198 journeyman, $330 master.

Do not let a renewal slip far — a plumbing license holder who renews 365 or more days late is treated as a new applicant and must re-test.

Check the fee numbers you find online, too: older application packets still show $190 journeyman, $310 master and $90 apprentice, while the OPLC fee page we read in September 2026 lists $198, $330 and $88.

Yes, by two routes.

Under New Hampshire's 2023 reciprocity law (HB 594, RSA 310:17), OPLC lists 34 qualifying jurisdictions for journeyman plumbers and 9 for master plumbers; the master list is Colorado, Connecticut, Delaware, Florida, Louisiana, Michigan, Rhode Island, Utah and Vermont.

OPLC's reciprocity page carries the full journeyman list, so check it for your state before you apply.

The second route is the exam: a journeyman licensed in another state can qualify for the New Hampshire journeyman license by passing the New Hampshire journeyman exam with at least 70%.

New Hampshire's public license lookup for mechanical licenses, plumbing included, is at forms.nh.gov/licenseverification.

Search it before you hire a plumber, take a job with a shop that says it is licensed, or sign an apprenticeship agreement with one.

Gas work is licensed separately from plumbing: it still requires a fuel gas license.

A licensed New Hampshire plumber can add a fuel gas piping installer license by completing 60 hours of approved training.

On backflow and medical gas, our research found no separate backflow-tester or medical-gas license under the Mechanical Licensing Board, and backflow devices are among the plumbing exam topics — but that absence was not affirmatively verified, and New Hampshire DES may certify backflow testers separately, so ask the board.

New Hampshire also certifies water treatment technicians under the same board.