Maryland Master Plumber Exam Prep

About the Maryland Master Plumber license

Maryland licenses plumbers through the Maryland State Board of Plumbing, part of the Maryland Department of Labor. The credential is formally the Master Plumber/Gas Fitter license — Maryland licenses plumbing and gas fitting together at every level (apprentice, journey, master), so a Maryland master plumber is also licensed to do gas fitting work. It requires you to first hold a Journey Plumber/Gas Fitter license, accumulate additional documented experience as a licensed journeyman, and pass a more demanding written exam that adds system design, sizing, and code-administration content. A master may design plumbing systems, pull permits, supervise journeymen and apprentices, and serve as the qualifying individual for a licensed plumbing contractor.

Your exam is built on the International Plumbing Code (IPC) — Maryland is an IPC state, not a UPC or NSPC state. As of the current PSI candidate bulletin, both the exam and the reference material you're permitted to bring are keyed to the 2018 IPC and 2018 International Fuel Gas Code (IFGC); this can lag the newest edition Maryland has adopted for general construction, so always confirm the exact edition required on the current bulletin before you buy or tab a code book. The two model codes — the Uniform Plumbing Code (UPC) published by IAPMO and the International Plumbing Code (IPC) published by the ICC — agree on the physics but differ in tables, fixture-unit values, and some sizing methods, so always work from the one your state adopted.

Know these scope facts cold: the license is held by the individual; most work requires a permit and inspection (rough-in/top-out and final); you must work within the classification you hold; and unlicensed or out-of-scope plumbing work is a violation that can cost you the license and carry penalties. Plumbing protects public health — the exam constantly returns to the two core purposes of the code: deliver safe potable water and remove waste without contaminating that water.

How Maryland licensing works

• Experience: Apprentice → Journey Plumber/Gas Fitter requires 4 years (at least 7,500 hours) under the direction of a licensed Master Plumber. Journey → Master requires an additional 2 years (at least 3,750 hours) working as a licensed Journey Plumber under a licensed Master Plumber. Hours must be certified in writing by the supervising Master Plumber; hours worked unlicensed, or certified by non-licensed office staff, do not count.
• Backflow course: every Master Plumber/Gas Fitter applicant must also complete a non-expired, approved 32-hour Backflow Prevention Device Testing course before applying to sit for the exam.
• Application: apply online through PSI (mail, fax, and email applications are no longer accepted) with fees, certification of your experience, and proof of the backflow course before you are approved to sit.
• Exam vendor and format: PSI Services LLC, under contract to the Board. The Master Plumber/Gas Fitter exam is 100 questions in 240 minutes, open-book (indexed/tabbed but unmarked reference books only — no study guides allowed in the room), with a passing score of exactly 70 percent. Gas Appliances and Piping is 40 of the 100 questions — by far the heaviest topic — followed by Drain, Waste, and Vent Systems (13) and Backflow Prevention (10). There is no separate business-and-law section on the Maryland exam.
• Renewal: licenses renew every 2 years. Maryland currently requires no continuing education to maintain an apprentice, journey, or master plumber license — confirm this hasn't changed before you rely on it.
• Local add-on exams: if you intend to work in Baltimore County, Prince George's County, or Montgomery County, the state license alone may not be enough — these jurisdictions can require an additional local examination (Baltimore County's own Plumbing Board; the Washington Suburban Sanitary Commission, WSSC, for Prince George's and Montgomery Counties). Contact the local board before assuming your state license covers work there.