The Maryland Master Plumber & Gas Fitter Guide

What Is the Maryland Master Plumber License?

In Maryland, plumbing and gas fitting are licensed together at the master level. The Master Plumber/Gas Fitter exam is one combined examination, not two separate tests: a single 100-question session that covers both the plumbing content a master plumber owns — water supply, drainage, vents, fixtures, backflow — and the fuel-gas content a gas fitter owns — gas appliances and piping under the IFGC. Passing it earns the master credential that lets you move beyond the journeyman scope of work and take responsibility for complete plumbing and gas-fitting jobs under the codes.

The exam is administered by PSI at computer-based testing centers, and the licensing program sits under the Maryland Department of Labor. The official candidate information bulletin (updated September 1, 2024) is published at labor.maryland.gov/license/pl/pl-psibulletincandidateinfo.pdf and is the authoritative source for the format, content outline and reference rules described here.

You are already an experienced plumber or gas fitter — this is the step from installing under supervision to owning the design, code-compliance and safety decisions on a job. The exam assumes journeyman-level command of the plumbing trade before it tests the master-level judgment on top, which is why the blueprint leans so hard on the gas-piping systems a master takes responsibility for every day.

Eligibility: The Journey-to-Master Path Runs Through Maryland

Maryland licenses plumbing at two levels, and the master exam sits at the top of the ladder. The related Journey Plumber/Gas Fitter exam is the same format — 100 questions, 240 minutes, open book, 70% passing — with a nearly identical content outline. The journey outline is the master outline minus the Special Topics category, and it counts 8 items for Plumbing Fundamentals and Safety instead of the master level's 5. The master exam is the next step: the same open-book format, tested at greater depth and with the full 10-topic blueprint.

The eligibility requirements themselves — the experience you must document and the application you must file — are set by the State of Maryland, not by the exam vendor. The Department of Labor governs who may sit, and PSI administers the test for approved candidates:

• Confirm the requirements first: contact the Maryland Department of Labor for the current experience and application requirements for the master plumber/gas fitter license before you invest in prep or book a test date.
• Meet the experience bar: the state determines what trade experience qualifies you for the master exam — plan your application around the requirements in effect when you apply.
• Registration is valid one year: once registered, you have a year to take the exam, so time your preparation before you register rather than after.
• Verify against the bulletin: the PSI Candidate Information Bulletin is the source of truth for exam mechanics; the Department of Labor is the source of truth for eligibility.

Exam Format: 100 Questions, 240 Minutes, Bring-Your-Own Open Book

The Maryland Master Plumber/Gas Fitter exam is a single, computer-based session delivered by PSI:

• 100 questions in 240 minutes. Four hours for the full combined exam, covering plumbing and gas fitting together.
• 70% passing score. You need 70 of the 100 questions correct to pass.
• Bring-your-own open book. Candidates bring their own permitted references to the test center — nothing is provided at the center. Only the references on the permitted list are allowed, and no study guides are permitted.
• Strict book rules. Reference books may be indexed, highlighted or underlined but must be unmarked otherwise — no writing in the books. Tabs must be permanent adhesive tabs; Post-It style flags are not allowed.
• Combined content. Plumbing and gas content share one session and one score — there is no separate gas-fitter sitting and no separate plumbing sitting.

Read the open-book rules twice, because they are the opposite of a “memorize it” exam: Maryland hands you nothing at the center, so your success is decided before exam day, by the books you bring and how well you know them. With 100 questions in 240 minutes you have about two and a half minutes per question — enough to look up a code section if you know where it lives, not enough to hunt. The exam rewards plumbers who know the structure of the IPC and IFGC cold: which chapter covers which topic, where the tables live, and how the index and section numbering get you to the answer fast.

The Official Blueprint: Gas Is 40 of 100 Questions

The Maryland bulletin publishes the official content outline for the 100 scored questions, and one number jumps off the page: 40 questions — 40% of the entire exam — are Gas Appliances and Piping. Study time should track these official weights:

The pattern is unmistakable: Gas Appliances and Piping (40) is not merely the heaviest subject — it is four times larger than the next biggest column. With Drain, Waste and Vent Systems (13) and Backflow Prevention (10), those three areas alone account for 63 of the 100 questions. Water Supply Systems (8) and Plumbing Mathematics (7) form the next tier. Master the heavy columns first: gas piping under the IFGC 2018 is worth more scored questions than every plumbing-content area combined — the fuel-gas code deserves a seat at the center of your study plan, not the edge.

Permitted References: Bring Your Own, Prepared Within the Rules

Maryland does not supply reference material at the test center — and it does not let you bring anything you like. The bulletin lists exactly what may come into the exam room, and candidates must bring their own copies:

The marking rules matter as much as the list itself. Your reference books may be indexed, highlighted and underlined — but they must be unmarked otherwise, meaning no writing in the books. Tabs are allowed only as permanent adhesive tabs; Post-It style flags are not permitted. Only the references on the permitted list may be brought in, and no study guides are allowed. That combination — bring your own, but prepared only in specific ways — makes the books themselves part of the test. Set your permanent tabs before exam day and practice navigating with the exact books (and exact tab layout) you will carry into the test center.

Code Edition: IPC 2018 and IFGC 2018, With State Rules on Top

The Maryland exam is built on the International Plumbing Code (IPC) 2018 and the International Fuel Gas Code (IFGC) 2018 — the 2018 editions, not a later one. If you trained on a newer code cycle, check your references: bring the 2018 edition to the test center, and re-learn any provisions that changed after 2018. Where Maryland state code or law conflicts with the national codes, the state rules govern — so before exam day, confirm any Maryland-specific provisions that override the model codes.

Fees, Registration & Retakes

• Exam fee: $65 for the Master Plumber/Gas Fitter exam.
• Registration validity: your registration is valid for one year — schedule and sit within that window, and time your registration so your prep is finished before it starts counting down.
• Vendor: exams are delivered by PSI for the Maryland program, on the official blueprint described above.
• Retakes: check the current PSI Candidate Information Bulletin for the retake policy and any re-registration requirements — the bulletin, not a prep site, is the authority on how a retake is scheduled and paid for.

Because the exam is a single combined session scored as one 100-question test, a retake is a reset of the entire blueprint — plumbing and gas together. There is no “pass the gas half and skip the plumbing half” shortcut: prepare for all ten content areas on every attempt.

How to Prepare

1. Confirm your eligibility and registration window. Contact the Maryland Department of Labor for current requirements before you buy prep or book anything. Registration is valid one year, so finish your studying before you register, not after.
2. Assemble the exact permitted reference set. IPC 2018, IFGC 2018, Mathematics for Plumbers and Pipefitters (Smith, 8th edition), a standard backflow text and 29 CFR Part 1926. Study with the same books — and same editions — you will carry into the test center, because Maryland provides none.
3. Prepare your books within the rules. Highlight, underline and index freely, but write nothing. Set permanent adhesive tabs for the heavy chapters and the tables you will need, and rehearse with that exact layout — Post-It flags will not be allowed on exam day.
4. Learn the code maps of both codes. Know the IPC structure for fixtures, water supply, drainage and vents, and the IFGC structure for gas piping and appliance venting. Practice index-first lookup and table recall until finding a code section takes seconds, not minutes.
5. Weight your study to the blueprint. Gas Appliances and Piping is 40 of 100 questions — give the IFGC at least as much time as the IPC. Then build out Drain/Waste/Vent (13), Backflow Prevention (10), Water Supply (8) and Plumbing Mathematics (7) before the 3–6 question subjects.
6. Drill the calculations with the math text. Plumbing Mathematics (7 questions) rewards practice with the Smith reference: fixture-unit values, pipe sizing and the load calculations a master runs daily. Know where each formula and table lives in the book before exam day.
7. Simulate under exam conditions. Full-length, timed, 100-question runs in 240 minutes at least once a week in the final month, aiming comfortably past the 70% line — with your actual reference books open, exactly as on exam day.

MasterPlumberPractice is built for exactly this exam: code-referenced questions aligned to the Maryland subject blueprint, the IPC and IFGC content areas the state weights, full-length timed simulations of the 100-question format, complete IPC theory and an AI tutor — practice the actual subject blueprint with our simulations so the real exam feels like a repeat. Start with free practice questions to feel the open-book format, and create a free account to track your scores as you go.

Frequently Asked Questions

Ready to Earn the Maryland Master License?

The master plumber/gas fitter license is the credential that lets you take full responsibility for plumbing and fuel-gas work in Maryland — and with gas worth 40 of the 100 questions, preparation has to cover both codes, not just the plumbing one. Start with the official blueprint: learn the codes with our IPC theory guides, try free open-book practice questions, register free and see the all-inclusive pricing — one subscription covering the Maryland blueprint and every state's master plumber exam line, so you never buy subject-area prep piece by piece.