If you’re a master plumber in another state, your New Hampshire plumbing license won’t start at master. The board’s rules say you must first hold a New Hampshire journeyman plumber license for at least 6 months before you’re eligible for master. Plan for that gap before you promise anyone a start date.
Here’s the short version. Plumbers are licensed at the state level, not by your town. The state issues apprentice, journeyman, and master plumber licenses, plus a separate business entity license for plumbing companies. Towns still handle permits and inspections, but they don’t issue the license itself.
Requirements change, so always confirm with the Mechanical Licensing Board before you apply. This page is a plain-English summary, not legal advice.
Who runs plumbing licensing in New Hampshire
Plumbing licenses are handled by the Mechanical Safety and Licensing Board, which sits inside the NH Office of Professional Licensure and Certification (OPLC). State law (RSA 153:27 through 153:38) calls it the Mechanical Licensing Board. It covers plumbers, gas fitters, oil heating technicians, and water treatment technicians.
The board moved from the Department of Safety to the OPLC on July 1, 2021. Its office is at 7 Eagle Square, Concord, NH 03301, and the phone number is 603-271-2152.
License types
New Hampshire uses these plumbing licenses:
- Plumbing apprentice. You’re learning the trade under a licensed NH master plumber. You must be at least 16.
- Journeyman plumber. You install, maintain, and repair plumbing under the direction of a master plumber. You must be at least 18.
- Master plumber. The license for people who run plumbing work as a business, either hiring others or doing it themselves. A master is also treated as qualified as a journeyman.
- Mechanical business entity. Required for companies doing plumbing in NH, including sole proprietors. At least one officer or responsible managing employee must hold a NH master plumber license.
A licensed plumber can also add a fuel gas piping installer license by finishing 60 hours of approved gas piping education. That’s a separate endorsement, not part of the plumbing license.
Hours and experience
For a journeyman plumber license, the rules (Mec 305.01) require all of the following:
- An apprenticeship completion certificate from the U.S. Department of Labor, or from the plumber who sponsored your apprenticeship.
- At least 600 hours of education covering drainage, venting, plumbing theory, plan reading, water supply protection, backflow, fixture sizing, accessibility, testing, the adopted codes, and NH plumbing law.
- At least 8,000 hours of on-the-job experience in plumbing.
As an apprentice, you work under a licensed NH master plumber. For your first 2 years, that supervision has to be direct supervision. After that, a lower level of supervision applies. State law caps it at 2 apprentices per licensee.
For a master plumber license, you need to have held a NH journeyman license for at least 6 months, have no consumer complaints that led to board discipline in the past year, and pass the master exam.
Exams
NH plumbing exams are given by Prov, Inc. under contract with the OPLC. You register on Prov’s site, and the OPLC decides whether you’re eligible to test. Prov’s candidate bulletin lists three plumbing exams:
- Journeyman Plumber: 85 questions, 3 hours.
- Master Plumber: 100 questions, 3 hours.
- First Year Plumbing Apprentice Bypass: 100 questions, 3.33 hours. The bulletin doesn’t explain who this one is for, so ask the board.
The exams are multiple choice and computer based, taken at a test center or remotely. You can bring your own copy of the approved references (the bulletin lists the 2018 International Plumbing Code and the NH administrative rules). No handwritten notes or sticky tabs. Each attempt costs $90. You can retake as often as needed within your 1-year eligibility window, with 2 days between attempts.
Heads up on passing scores. Prov’s bulletin (dated January 2025) says 70% on all plumbing exams. The board’s rules say 70% for the journeyman exam but 75% for the master exam. Those don’t match, so call the board and aim for 75% on the master exam to be safe.
Fees and renewal
OPLC fees (rule Plc 1002.25, current as of July 1, 2025) are the same for initial, renewal, and reinstatement:
- Apprentice plumber: $88
- Journeyman plumber: $198
- Master plumber: $330
- Mechanical business entity: $275
Each license covers 2 years. Prov’s $90 exam fee is paid separately. A business owner who is the only licensee and has no plumbing employees is exempt from the business license fee until they take on apprentices or licensed plumbers.
Individual licenses expire every 2 years on the last day of the month they were issued. Miss it and your license is expired, and working on it counts as unlicensed work. You can get reinstated within 1 year by doing the renewal steps and CE. After more than 1 year, you apply as a new applicant.
Continuing education
Journeyman and master plumbers need at least 6 hours of CE per 2-year cycle for each plumbing endorsement. That means board-approved seminars of at least 3 hours each, in a classroom, covering NH’s adopted plumbing code and current licensing laws and rules. You can’t get credit for repeating the same seminar in one cycle. Bring your license, a photo ID, and your code book.
Apprentices don’t take CE. Instead, at renewal you show proof you’re still enrolled in your apprenticeship.
Bond and insurance
The board’s rules don’t require a bond for individual plumbers. Business entities must show proof of liability insurance and good standing with the NH Secretary of State to get or renew the business license. The rules don’t set a minimum coverage amount, so ask the board what they accept.
Reciprocity and out-of-state plumbers
State law lets the board sign reciprocity agreements with states whose requirements are equal to or tougher than New Hampshire’s. The rules don’t list any active agreements, so don’t count on one. Ask the board.
What the rules do spell out: if you hold a journeyman license in another state, you can qualify for the NH journeyman license by showing that license and passing the NH journeyman exam with 70% or better. Out-of-state licensees still have to meet NH’s experience requirements for the level they want. And remember, master requires 6 months holding a NH journeyman license first.
How to apply
- Apprentice: Send the board application with a signed letter from your sponsoring NH master plumber (or a U.S. Department of Labor apprenticeship agreement) and the $88 fee.
- Journeyman: Pass the Prov exam, then send the application, your apprenticeship completion certificate or sponsor affidavit, one letter from the licensed plumber who supervised you, your exam score, and the $198 fee.
- Master: Pass the master exam, then send the application, a letter from the licensed plumber who supervised your journeyman work, your score, and the $330 fee.
If you have certain criminal convictions, you’ll also need a criminal records check. The board says it will approve or deny a complete application within 60 days. You can check a license’s status with the license lookup on the OPLC website.
FAQ
Do I need a license from my town to do plumbing in NH?
No. The license comes from the state. Your town issues permits and inspections, and a licensed plumbing business can pull permits in any NH municipality.
Can I do my own plumbing?
Yes, in your own single-family detached home or townhouse, including new construction. The work still has to meet the state plumbing code and any local permit rules.
How long does it take to become a journeyman?
The rules require 8,000 on-the-job hours plus 600 education hours. At full-time hours, that’s roughly four years, but it depends on your schedule and program.
Have the rules changed recently?
Yes. The board’s licensing and renewal rules were readopted effective February 13, 2026, and the fee schedule was updated July 1, 2025. Check the board’s page for the latest forms before you apply.
Next steps
Compare rules across the country on our plumbing license by state page, or start with the full plumbing license guide. Ready to go out on your own? Read how to start a plumbing business. Working near the border? See the Massachusetts plumbing license guide too.
