Maine Master Plumber License
What Makes the Master License Different
The Master Plumber license is the highest trade credential in Maine. It authorizes you to plan plumbing systems, pull municipal permits, serve as the license of record on permitted projects, supervise apprentices and trainees, and operate an independent plumbing business.
A Journeyman can do the physical work, but every permitted project needs a Master behind it. If you want to run your own shop or take on contracts directly, this is the license you need.
Two Experience Tracks
Track A — Licensed Journeyman. Document 2,000 hours (minimum one year) of plumbing installation work as a licensed Journeyman Plumber. All hours must be accumulated after your Journeyman license was issued and under the supervision of a Master Plumber. Your supervising Master signs a notarized Experience Affidavit.
Track B — Direct Trainee to Master. Document 8,000 hours (minimum four years) of plumbing installation work as a licensed Trainee under a Master Plumber. This path bypasses the Journeyman tier entirely. It's a longer road, but it's available for tradespeople who've been working under a Master for years and want to go straight to the top credential.
Both tracks require passing the Master Plumber exam.
The Master Exam
Submit the Master Plumber Examination Application to the Board with your notarized affidavits, transcripts (if applicable), and the application fee. After the Board reviews and approves your package, you'll receive an email authorization to schedule with Prov, Inc.
The Master exam is closed-book, timed, and requires a 75% passing score — five points higher than the Journeyman's 70% threshold. The exam is based on the 2021 Uniform Plumbing Code as adopted by Maine (with all state amendments and exclusions). Pay the $65–$90 exam fee directly to Prov.
Testing centers: Auburn, Bangor, Calais, Portland, Presque Isle. Remote proctoring is also an option. You'll receive your score immediately after completing the test.
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After You Pass
Submit the final licensure application through OPOR's online portal. Pay the $200 license fee and $21 background check fee. OPOR runs a criminal history check, and once cleared, the Board activates your license. There's no physical license card — your credential arrives as a PDF from [email protected].
The License Is Not a Business License
Passing the Master exam proves your trade competency. Operating a plumbing contracting business requires separate steps: registering your business entity (LLC, corporation, or DBA) with the Maine Secretary of State, setting up tax accounts with Maine Revenue Services, obtaining a federal EIN as applicable to the entity and tax accounts, and securing insurance.
Workers' Compensation is mandatory for any Maine construction business with one or more employees. Self-employed Masters with no employees are technically exempt from the state mandate, but most general contractors and commercial clients require proof of WC coverage before awarding subcontracts.
General liability insurance isn't state-mandated for plumbing licensees, but local code enforcement offices commonly require proof of coverage before issuing municipal permits.
Renewal
Master licenses renew on a biennial cycle. The renewal fee is $200. Late renewal within 90 days of expiration triggers a $50 late fee. Between 90 days and two years, reinstatement costs $100. Beyond two years, you must re-apply and re-take the exam.
The Maine Plumber License Guide covers the full Master pathway, including the business formation steps that follow licensure.
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