Montana Plumbing License: The Board Rewrote the Exam, and the Code Just Changed (2026)

Montana licenses plumbers at two levels, journeyman and master, through the Montana Board of Plumbers inside the Department of Labor & Industry. Both levels require passing a Board-prescribed exam, and in 2026 the Board rewrote that exam twice over, changes most guides to Montana plumbing licensing have not caught up with yet.

At a glance

• Two licenses: journeyman (5 years, 7,500 hours) and master (4 years as journeyman, 6,000 hours minimum)
• The hands-on practical exam ended April 11, 2026; journeyman applicants now take two written exams
• Montana's plumbing code became the 2024 Uniform Plumbing Code on September 26, 2026
• Temporary practice permits run 110 days
• Licenses expire every September 1, with 4 hours of continuing education required to renew

New to licensing in Montana? Start with the Montana contractor license requirements, and for every other state see how to get a contractor license in each state.

The Two Montana Plumbing Licenses

Montana Code Annotated § 37-69-301(1) states it plainly: except for the listed exceptions, a person working at the field of plumbing in Montana, "either as a master plumber or as a journeyman plumber, shall first obtain a license."

There are two licenses. There is no separate plumbing contractor license issued by a contractor board, and there is no apprentice license, since apprentices register with the Department rather than being licensed. Montana also issues a medical gas endorsement as an add-on credential, not a standalone license.

§ 37-69-301(2) adds a duty most states leave out of statute: a licensee "shall carry the license, or proof of licensure, at all times while working on a job site and performing work that requires a license." The Board determines what counts as acceptable proof. Leaving the card in the truck is a statutory violation in Montana, not a technicality.

Journeyman Plumber: Requirements

Under § 37-69-304(1), a journeyman applicant needs a specific record of 5 years of legally obtained experience in the field of plumbing, satisfied either by:

• 5 years in a major phase of the plumbing business, verified by time or pay records; or
• completion of an apprenticeship program meeting standards set by the Department or the U.S. Department of Labor, Bureau of Apprenticeship.

Credit toward the experience requirement may be given for time spent at an accredited trade or other school specializing in plumbing training, if the Board approves it. The Board's current application states the standard as 5 years and 7,500 aggregate hours, documented on an Experience Verification Affidavit that each employer you want counted must complete separately. The affidavit carries an explicit instruction: the applicant cannot verify their own hours.

The sentence that decides who you can work for

§ 37-69-304(2) is the most consequential sentence in Montana's plumbing chapter, and it still appears on the Board's application form:

"A licensed journeyman plumber may perform work only in the employment of a licensed master plumber unless otherwise permitted by rule of the board. Performing work in the employment of a licensed master plumber means the licensed master plumber shall observe the journeyman plumber's work at different times over the course of employment and for different levels of plumbing work."

The statute does not merely require a master plumber's name on an org chart. It defines "in the employment of" as actual, repeated observation across different times and different levels of work. A master plumber whose only connection to a company is a signature on a form is not, by the statute's own definition, employing anyone. That is the reason a compliant qualifying-agent arrangement has to be genuine, which we return to below.

Master Plumber: Requirements

Under § 37-69-305(1), a master applicant must show:

• 4 years of experience as a licensed journeyman plumber in the field of plumbing, verified by time or pay records; and
• 3 years of experience, which may run concurrently with the 4 years, either working with a licensed master plumber or in a supervisory capacity; and
• satisfactory completion of the Board's master examination.

§ 37-69-305(2) defines a year precisely: "1 year of experience is 1,500 hours or more of work in a continuous 12-month period." The Board's master application translates the requirement as 4 years and a minimum of 6,000 hours, which is exactly 4 times 1,500. A calendar year with fewer than 1,500 hours worked does not count toward the total, regardless of what the calendar says.

The three supervised years run concurrently with the four journeyman years. It is not 7 years total. A number of competing guides present it as sequential, adding three years to a timeline Montana never asked for.

The experience that does not count

The Board's master checklist contains a restriction rarely covered elsewhere:

"Practice in the fields of steam fitting, hydronics, and industrial piping will not be considered as acceptable experience in the field of plumbing for the master license experience requirement."

If a meaningful share of your journeyman-level hours came from hydronic heating or industrial process piping, document your sanitary and potable-water work separately from the start, since those hydronic hours may not carry you to master.

The Exams: What Changed in 2026

Two separate rule changes, both now in force, mean the exam Montana actually administers today looks different from the one described almost everywhere online, including on some of the Board's own older documents.

The hands-on practical is gone. Effective April 11, 2026, the Board amended ARM 24.180.407 and eliminated the separate hands-on practical examination. A journeyman applicant now completes two written examinations, each requiring a score of 70% or greater, and must pass the first before scheduling the second. The Board's stated reason: it no longer administers a separate hands-on practical, both components are now delivered in written format, and a written-only model costs less and is easier to administer consistently. The master exam is unchanged: one written examination, 70% to pass.

The code edition changed too. Montana's building code rules, ARM 24.301.301, were amended to adopt the 2024 Uniform Plumbing Code, effective September 26, 2026, replacing the 2021 edition that governed the prior exam cycle. The Department's own current-codes listing confirms the 2024 UPC as the code now in force.

Neither change has reached every Board document yet. The Board's exam information sheet and its journeyman and master application checklists are still dated 2023, and they still describe the single written exam plus hands-on practical, and the 2021 code, that applied before April and September of 2026. IAPMO's Montana testing page likewise still links a page of "2021 Mt Amendments." None of that makes the older documents wrong as of when they were written, it means a candidate studying from them today is studying the prior format. Confirm the current exam structure, code edition, and amendments packet directly with the Board and with IAPMO before you schedule.

What stays the same: exams are still administered by IAPMO, scheduled online through its FLEX testing platform after the Board sends an approval letter. Candidates must bring their own, non-photocopied Uniform Plumbing Code book, since none is supplied at the exam, and a simple non-scientific calculator is allowed. Examination fees are paid directly to IAPMO, separately from the Board's application fee.

The failed-exam consequence rule was not touched by the 2026 amendment and still reads as written. ARM 24.180.407(3) provides that if an applicant fails three written examinations within the one-year period of an application's viability, the applicant must complete 20 hours of continuing education before being approved to sit a fourth time. An applicant who fails the fourth written examination may not reapply for licensure for one year.

How to apply for a Montana journeyman license by examination

1. Document your experience, either 5 years in a major phase of plumbing or a completed apprenticeship, using the Board's Experience Verification Affidavit.
2. Submit the journeyman application and the $220 application fee to the Board.
3. Wait for Board approval, which it will confirm with an admission letter and, if you request one, a temporary practice permit.
4. Schedule and pass the first written exam through IAPMO's FLEX platform, then the second, each at 70% or better.
5. Receive your license once the Board processes your complete, routine application, typically within 30 days.

The Temporary Practice Permit and Its 110-Day Clock

Montana lets you work while your application is pending, on terms set by ARM 24.180.607:

• An applicant for either the journeyman or the master license may receive a temporary practice permit, but it authorizes only journeyman functions. Master applicants holding a temporary permit may not perform work requiring a master license.
• The permit is issued upon Board approval to take the exam and receipt of the appropriate fee.
• The permit terminates 110 days after issuance, or upon the applicant's fourth failure of the written examination, or upon failure of the practical examination with a score below 65 percent, whichever comes first.
• A second temporary permit goes to an applicant who scores between 65 and 69 percent on the practical, or, at the Board's discretion, to an applicant who could not sit a scheduled practical because of a documented hardship.

The journeyman application also requires naming the Montana master plumber you will be employed by and that master's license number to receive the temporary permit, the same § 37-69-304(2) standard applied at the permit stage.

Verified Fees

Montana cut these fees on July 11, 2026, when the Board amended ARM 24.180.401 (MAR Notice No. 2026-79.2) to bring its cash balance back within the statutory cap in § 17-2-302 and § 17-2-303, MCA. The Board's own application checklists, still dated February 2023, have not been updated and still show the pre-cut amounts; the figures below are the current rule text.

Notes:

• Before July 11, 2026, the journeyman and reciprocity/out-of-state application fees were $270 and $400; the master application fee was $380. All three dropped to a flat $220 under the amended fee schedule. A separate $400 board-administered exam/reexamination fee was also repealed outright, since exams are now handled entirely through IAPMO.
• All Board fees are non-refundable, and checks are payable to the Board of Plumbers.
• IAPMO sets and collects its own exam fees separately from the Board; confirm the current amount with IAPMO before you budget.
• A complete, routine application is processed within 30 days. Non-routine applications must be complete 15 days before a Board meeting and may require an appearance before the Board.

Renewal and Continuing Education

Montana plumbing licenses expire annually on September 1. Renewal requires 4 hours of Board-approved continuing education completed before the next renewal cycle. New licensees are exempt from the CE requirement during their first renewal cycle, but a licensee moving from journeyman to master is not exempt and still owes at least four hours.

A 2025 legislative change, HB 276, now requires every licensee and applicant to keep a current mailing address on file with the Department and to report any address change within 30 days. Licensees may also consent to receive legal notices by email instead of mail. The Board still mails a renewal notice roughly 45 days before expiration to the preferred address on file, but keeping that address current is now a standalone statutory duty, not just good practice.

Who Does Not Need a License

§ 37-69-102(1) lists the permanent exceptions. Licensure is not required when:

• an owner of a single-family residence used exclusively for personal use installs all sanitary plumbing and potable water supply piping, or a mobile home or manufactured housing dealer connects a home to existing facilities during delivery and setup;
• the work is in any mine, mill, smelter, refinery, or railroad;
• the work is on a farm or ranch not connected to public water supply and sewage disposal systems;
• cities, towns, water districts, and water user associations extend, repair, or replace their own water and sewer mains;
• the work is installation of water conditioner services in private dwellings;
• it is minor work by employees or agents of an appliance dealer incidental to installing an appliance purchased from the dealer;
• a qualified person appointed by the water system's administrative authority installs a water meter;
• for a private water supply, the work is installing the pump, waterline, or pressure tank, inside or outside the structure;
• the person is a registered apprentice working under a licensed plumber's supervision; or
• the person is a student enrolled in an accredited plumbing training program doing classroom or lab assignments. That exception does not authorize work that will be incorporated into an occupied structure or connected to a system requiring a licensed plumber.

§ 37-69-102(3) adds a rarely used safety valve: if no licensed person is available, a county, city, or town council or commission, or a water or sewer district board, may authorize an unlicensed person to perform plumbing work on a temporary basis, after giving the Board reasonable notice by certified letter and either receiving approval or getting no response within 30 days of the postmark. The authorization must be withdrawn once a licensed person is reasonably available.

The Business Layer: Master Plumber of Record

Holding a master license is not the same as being the licensed person a plumbing company operates behind. Montana handles that with a separate designation called the Master Plumber of Record, governed by ARM 24.180.507.

The Board's Master Plumber of Record form opens by reciting the authority the designation carries:

"A master plumber is the only person authorized by Montana law to plan, estimate, bid, contract for and supervise plumbing work in the state of Montana, and may do the work of a journeyman plumber."

Under ARM 24.180.507, the master plumber of record is responsible for supervising all plumbing work performed by the plumbing business for which they are designated, and may be the master of record for only one plumbing business at any one point in time. Designation and termination must be reported to the Board in writing, and no change of status is lawful until the Board receives actual written notice. We break the whole mechanism down in Montana's Master Plumber of Record rule.

Reciprocity and Out-of-State Experience

Montana used to run journeyman reciprocity through a dedicated rule, ARM 24.180.603, naming Oregon, Idaho, North Dakota, and South Dakota. That rule was repealed effective April 11, 2026, as duplicative of Montana's general licensure-by-endorsement statute, § 37-1-304, MCA.

Under the general statute, an applicant with an active, good-standing out-of-state license qualifies for licensure by endorsement if that state's requirements are substantially equivalent to Montana's at the time of application. The Board may still maintain reciprocity agreements with specific states, but any such agreement cannot let an applicant in without meeting a standard substantially equivalent to Montana's own. The Board's own checklists, still dated 2023, continue to name the repealed rule and the same four states, so an out-of-state applicant should confirm current reciprocity status directly with the Board rather than relying on the older paperwork.

Applicants from a state with no journeyman or master licensing of its own may instead submit a notarized statement from a qualified individual with direct knowledge of their experience, equivalent to 5 years for journeyman or 9 years for master.

Where a Qualifying Agent Fits in Montana

If you own a plumbing business in Montana and you are not personally a licensed Montana master plumber, you have two honest routes: earn the credential yourself, or employ a licensed Montana master plumber who takes the Master Plumber of Record designation for your company.

If you own a plumbing business in Montana and are not personally a licensed master plumber, a qualifying agent is the person who qualifies the company: an owner or full time W-2 employee who actually supervises the work. Companies that need that person but do not yet employ one typically turn to contractor qualifier services or hire a qualifying agent directly.

Montana's statutes make the shape of a compliant arrangement unusually clear, because the state defined the relationship in terms of conduct rather than paperwork:

• § 37-69-304(2) defines employing a journeyman as the master observing that journeyman's work repeatedly and across different levels of work.
• § 37-69-323 provides that a master plumber "may employ only apprentice plumbers registered with the state department of labor and industry and only journeyman plumbers who are licensed by the state of Montana," and makes the master responsible for ensuring that all work performed by those employees complies with the state plumbing code. That section exposes the master to unprofessional conduct charges under § 37-1-316 and liability for false swearing under § 45-7-202 for providing the Department false information about an employee's experience or skill.
• § 37-69-305(3) prohibits a master from allowing the license "to be used by any person or firm, corporation, or business other than the master plumber's own" for obtaining permits or doing plumbing work. The Board resolves what "own" means: the business with which the master plumber is associated as the master plumber of record.

Put together, Montana is describing someone genuinely inside the company: supervising the work, observing it in person, accountable for code compliance, and personally exposed if the paperwork is false. That is an employee, and The Licensing Company places qualifiers as W-2, full-time employees of the business they qualify, never on a percentage, a flat fee, a per-project arrangement, or a 1099. Some owners are told that paying an outside master plumber to put a name on paperwork, without real supervision, is a shortcut. Montana's statutes say otherwise, and the practice carries real legal exposure for everyone involved.

If you already hold a Montana master plumber license and want to put it to work properly, you can become a qualifying agent.

What's Coming: A 2027 Legislative Proposal

None of what follows is current law. In June 2026, a Department of Labor & Industry Licensing Reform Task Force construction subcommittee recommended that the full task force support a Board of Plumbing modernization bill for the 2027 Montana Legislative session.

As recommended, the bill would replace the current 5-year journeyman experience standard with a 4-year, 8,000-hour documented-experience pathway, aligned with a registered apprenticeship model, and give the Board authority to evaluate related instruction, incomplete apprenticeships, and out-of-state experience by rule. It would also convert medical gas piping credentialing from a separate state endorsement to a registration that recognizes a national certification, and would update job-site proof-of-licensure rules to match the approach Montana already uses for electrical licensing.

The proposal has not been introduced, let alone passed. Montana's current 5-year, 7,500-hour journeyman standard and the current medical gas endorsement remain in force. If you are planning a multi-year path to licensure, it is worth knowing this change is under discussion, but budget your timeline around the law as written today.

How Much Does a Montana Plumbing License Cost

The government side is knowable and listed above: the Board's application and license fees, IAPMO's exam fees, the $50 master plumber of record designation, annual renewal, four hours of continuing education, and whatever bonding and liability insurance your work and local jurisdiction require. All of those are set by the Board, the vendor, or your insurer, and all change, so verify before you budget.

The question business owners actually ask is different: what does it take to solve the problem of not having a Montana master plumber to carry the master plumber of record designation, so the company can legally bid and contract? That has no honest flat number. It depends on whether you already employ a Montana master, how quickly you need to be operating, how many states you are expanding into, and how long the arrangement needs to last. If that is where you are, hire a qualifying agent and start with your actual situation rather than a guess.

Montana Plumbing License FAQ

Does Montana have a state plumbing license? Yes. The Montana Board of Plumbers licenses journeyman and master plumbers statewide under Title 37, chapter 69. Apprentices register with the Department rather than holding a license, and there is a separate medical gas endorsement.

How many hours do I need for a Montana journeyman plumber license? Five years of legally obtained plumbing experience, which the Board's application states as 5 years and 7,500 aggregate hours, or completion of an approved apprenticeship program. Hours are documented on the Board's Experience Verification Affidavit, and you cannot verify your own.

How long does it take to become a master plumber in Montana? Four years as a licensed journeyman, with three of those years, running concurrently rather than consecutively, spent working with a licensed master or in a supervisory capacity. Under § 37-69-305(2), a year means 1,500 or more hours in a continuous 12-month period, so the Board's checklist states the total as 6,000 hours minimum.

Is the Montana journeyman plumber exam still a written test plus a hands-on practical? No. Effective April 11, 2026, the Board eliminated the hands-on practical exam. A journeyman applicant now passes two written examinations, each at 70% or better, with the first required before scheduling the second. The master exam remains a single written exam at 70%.

What plumbing code edition does Montana use now? The 2024 Uniform Plumbing Code, effective September 26, 2026, replacing the 2021 edition. Confirm the current amendments packet with the Board or IAPMO before you study, since some Board documents and IAPMO's testing page have not yet been updated to reference it.

Does Montana still have plumbing license reciprocity with Oregon, Idaho, North Dakota, and South Dakota? The dedicated reciprocity rule naming those four states was repealed effective April 11, 2026. Licensure by endorsement now runs through Montana's general statute, § 37-1-304, MCA, which requires a substantially equivalent out-of-state license; the Board may still honor agreements with those states, so confirm current status directly with the Board.

Can a journeyman plumber work independently in Montana? No. Section 37-69-304(2) provides that a licensed journeyman may perform work only in the employment of a licensed master plumber, and defines that employment as the master actually observing the journeyman's work at different times and across different levels of plumbing work.

Who can bid and contract for plumbing work in Montana? The Board's Master Plumber of Record form states that a master plumber is the only person authorized by Montana law to plan, estimate, bid, contract for, and supervise plumbing work in the state. A plumbing business operates behind a designated master plumber of record.

How often does a Montana plumbing license renew? Annually, expiring September 1, with four hours of Board-approved continuing education. New licensees are exempt during their first renewal cycle; plumbers upgrading from journeyman to master are not. Since 2025, licensees must also keep a current mailing address on file and report changes within 30 days.

Sources

• Montana Board of Plumbers FAQ, retrieved 2026-10-11
• Montana Board of Plumbers homepage, retrieved 2026-10-11
• Montana Plumbing Licensing Information / Exam Information sheet, retrieved 2026-10-11
• Journeyman Plumber Licensing Checklist, retrieved 2026-10-11
• Master Plumber by Examination Checklist, retrieved 2026-10-11
• Montana Code Annotated, Title 37, chapter 69, retrieved 2026-10-11
• Montana Code Annotated § 37-1-304, retrieved 2026-10-11
• Board of Plumbers Notice of Adoption, MAR Notice No. 2025-126.2, effective April 11, 2026, retrieved 2026-10-11
• Board of Plumbers Notice of Proposed Rulemaking, MAR Notice No. 2025-126.1, with full amended text of ARM 24.180.407, retrieved 2026-10-11
• Board of Plumbers Notice of Adoption, MAR Notice No. 2026-79.2, amending and reducing the Board's fee schedule, effective July 11, 2026, retrieved 2026-10-11
• Board of Plumbers Notice of Proposed Rulemaking, MAR Notice No. 2026-79.1, with the full amended ARM 24.180.401 fee table, retrieved 2026-10-11
• Department of Labor & Industry, Building Codes Program, Current Codes, retrieved 2026-10-11
• Notice of Proposed Rulemaking, MAR Notice No. 2026-95.1, "2026 Updates to the State Building Code" (dli.mt.gov), retrieved 2026-10-11
• IAPMO Montana Plumbing License Testing, retrieved 2026-10-11
• Licensing Reform Task Force, Construction Subcommittee memorandum and recommendation, June 2026 (Department of Labor & Industry, esd.dli.mt.gov), retrieved 2026-10-11

For help placing a licensed Montana master plumber as a compliant, W-2 qualifying agent, explore your options or call 615-219-2110. Browse guides for other states, or read about HVAC license Montana, electrician license Montana, and the national explainer on journeyman vs. master plumber.