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Maryland Journeyman Plumber / Gas Fitter — Practice Exam Guide

What This Practice Exam Covers

The Maryland Journeyman Plumber / Gas Fitter licensing exam consists of 100 questions answered within 240 minutes (4 hours). You must score 70% or higher — that means at least 70 correct answers — to pass.

This practice site offers two ways to prepare:

• Free practice exam: 10 questions per attempt, drawn from a limited question pool. You can retake it as many times as you like to get a feel for question style, phrasing, and format. It's a useful starting point, but the limited pool means you'll begin seeing repeated questions quickly.

• Full practice exam (paid): Mirrors the real exam with 100 questions and a 240-minute time limit. Questions are drawn from a pool of 716+ items, so every attempt generates a unique exam — no duplicate runs. Questions are built around the exact topic blueprint provided by the official test provider, giving you the most accurate simulation available.

Start free, then move to the full exam once you're ready to train at full intensity.

What You'll Be Tested On

Gas Appliances and Piping — 40 items

This is nearly half the exam. Expect questions on approved gas piping materials (metallic pipe, CSST, copper tubing, polyethylene), fitting types, and joint methods. You must be able to use gas pipe sizing tables — specifically IFGC Appendix B and Appendix D capacity tables — to select pipe diameter based on developed length and BTU load. Pressure testing and purging procedures are tested in detail: test pressures, gauging requirements, and leak detection methods per 2018 IFGC Sections 406.1 through 406.7. Combustion air is a major sub-area: confined vs. unconfined spaces, opening sizes, motorized louver interlocks (Section 304.10), and outdoor air requirements. Venting is equally heavy — vent types (B, BW, L), single-appliance vs. common vent systems, sizing by Table 503.4 and Table 503.10.5, termination clearances, and appliance draft hood rules. Know clearances for prohibited installations (Section 303.3, 303.7) and appliance location restrictions cold.

Drain, Waste, and Vent Systems — 13 items

This section tests calculation skills as much as code knowledge. Drainage fixture unit (DFU) values from IPC 2018 Table 709.1 must be memorized for common fixtures. You'll size building drains and horizontal branches using Tables 710.1(1) and 710.1(2). Slope rules for horizontal drainage piping (typically 1/4 inch per foot for pipe under 3 inches) and cleanout spacing, placement, and access requirements under IPC Chapter 7 are frequently tested. Vent pipe types — individual, circuit, wet, island — and sizing from IPC Table 906 appear, along with trap-to-vent distance limits and the developed-length rules governing vent connections.

Backflow Prevention — 10 items

Expect questions that ask you to match a specific hazard classification to the correct device type. High-hazard (contamination) connections require air gaps or reduced pressure principle assemblies; low-hazard (pollution) connections may use dual-check or pressure-type vacuum breakers. ASSE standards are tested by number: ASSE 1001, 1011, 1013, 1015, 1020, 1024, and others appear in IPC Table 608.1. Air gap dimensions, vacuum breaker installation heights, and specific connection rules — boilers, lawn irrigation, fire sprinklers, hose bibbs, carbonated beverage dispensers — are all fair game.

Plumbing Fundamentals and Safety — 8 items

Safety questions come directly from 29 CFR 1926. Employer accident prevention responsibilities (§1926.20), PPE selection and employer payment obligations (§1926.95), first aid requirements (§1926.50), and noise exposure limits (§1926.52) are all cited in the question bank. Know IPC scope, permit exemptions, and code official authority for the plumbing-side questions.

Water Supply Systems — 8 items

Pipe material selection (copper, PEX, CPVC, PVC, galvanized steel) by application, pressure-reducing valve thresholds, booster system requirements, and minimum flow rates at fixtures are covered. Joining methods by material type — solvent cement, solder, brazing, mechanical, push-fit — appear regularly, as do cross-connection control principles that overlap with Backflow Prevention.

Plumbing Mathematics — 7 items

Calculations include offset work (45°, 60°, 22.5° constants), rolling offsets, pipe length with fitting allowances, grade and drop calculations for drainage pipe, and volume/pressure calculations for cylindrical and rectangular tanks. These questions reward candidates who have practiced the arithmetic — they are not multiple-choice guessing territory.

Plumbing Fixtures, Fixture Fittings, and Plumbing Appliances — 4 items

Minimum fixture counts by occupancy type, fixture clearances and spacing, shower compartment dimensions, valve requirements, and water heater installation rules (location, access, drain valves, pressure marking per IPC 2018 Section 504.4.1 and 504.6) appear here.

Traps, Interceptors, and Backwater Valves — 4 items

Prohibited trap types, minimum and maximum trap seal depth (IPC Chapter 10, Section 1002.3 and 1002.4), grease interceptor sizing and grease retention capacity (Section 1003.3), and oil separator design specifications are tested. Know the grease interceptor exemptions.

Materials, Uses, and Specifications — 6 items

Approved vs. prohibited materials for gas piping, pipe identification markings, corrosion protection requirements, and plastic pipe limitations (polyethylene ASTM D2513 for underground gas only; PVC/CPVC prohibited for fuel gas) are the core focus.

Worked Sample Questions

Sample Question 1 — Gas Appliances and Piping

Where motorized louvers are used for combustion air openings, what safety provision is required regarding the main burner?

• A. The main burner must be equipped with a standing pilot light
• B. The louvers must be connected to a manual override switch accessible to the occupant
• C. A backup nonmotorized louver must be installed in a separate opening
• D. Means shall be provided to prevent main burner ignition if the louvers fail to open and to shut down the burner if the louvers close during operation

Correct Answer: D

The code requires an interlock — not a pilot light, a manual override, or a backup louver. Per 2018 IFGC, Section 304.10, motorized louvers must be proven to be in the full open position before the main burner fires, and the system must shut the burner down if the louvers close during operation. Distractors A, B, and C describe real-sounding provisions that do not exist in the code. This is a pattern the exam uses frequently in combustion air questions: the correct answer is the one that specifically addresses both startup and operating conditions.

Sample Question 2 — Drain, Waste, and Vent Systems

The upstream invert elevation of a drain is 101.50 feet and the run falls 6 inches. What is the downstream invert elevation?

• A. 101.00 feet
• B. 101.44 feet
• C. 100.50 feet
• D. 102.00 feet

Correct Answer: A

Convert 6 inches to feet: 6 ÷ 12 = 0.50 foot. Subtract the fall from the upstream elevation: 101.50 − 0.50 = 101.00 feet. Option B (101.44) results from an incorrect conversion. Option C (100.50) applies the full 1-foot subtraction, confusing inches with feet. Always convert units before calculating — this is the most common arithmetic error on drainage elevation problems.

Sample Question 3 — Backflow Prevention

A dual-check-valve-type backflow preventer conforms to which ASSE standard and is rated for which degree of hazard?

• A. ASSE 1015, low hazard
• B. ASSE 1024, low hazard
• C. ASSE 1024, high hazard
• D. ASSE 1022, high hazard

Correct Answer: B

Per IPC, Table 608.1 and Section 608.14.9, dual-check backflow preventers shall conform to ASSE 1024 and are rated for low hazard (pollution) applications only. A high-hazard connection requires a reduced pressure principle assembly (ASSE 1013) or air gap — not a dual check. ASSE 1015 covers the double check valve assembly, a different device. Confusing 1015 with 1024 is one of the most common errors in this topic area.

How to Read Your Score

The passing threshold is 70% — 70 out of 100 questions correct.

Treat your first practice attempt as a diagnostic, not a verdict. A score in the 50s tells you which topic areas need work, not that you cannot pass. A score of 68–72% on your first full-length attempt is a caution sign: you are close to the line, but "close" on a timed 100-question exam under test-day pressure is not the same as "ready." Aim for consistent scores of 80% or higher across multiple attempts before scheduling the real exam.

Use the topic breakdown after each attempt. If Gas Appliances and Piping (40 items) is your weakest area, every point you gain there has four times the impact of a point gained in Traps and Interceptors (4 items). Prioritize accordingly. Backflow Prevention (10 items) rewards memorization of ASSE standards and hazard classifications — a few hours with Table 608.1 can recover multiple points. Mathematics questions are fully recoverable with practice: the formulas are fixed, and speed improves with repetition.

Where Candidates Lose Points

Gas Appliances and Piping is where most points are won or lost — 40 items is an enormous share of the exam. Candidates commonly pick the wrong sizing table (Appendix B vs. Appendix D), misread BTU capacity vs. pipe length on the table axes, or miss the distinction between a single-appliance vent and a common vent system.

Combustion air questions trip up candidates who memorize the opening size formula but forget the motorized louver interlock rule (IFGC Section 304.10) or the confined-space exceptions.

Backflow Prevention losses come from mixing up ASSE standard numbers. ASSE 1013, 1015, 1020, 1024 — they are similar-looking numbers tied to very different devices and hazard levels. Candidates who have not drilled IPC Table 608.1 by device name and standard number guess on these questions.

Mathematics losses come from unit conversion errors — mixing inches and feet in drainage slope calculations, or forgetting to apply a fitting allowance before cutting pipe. These are solvable with a consistent, written process on every problem.

Time management is underestimated. At 240 minutes for 100 questions, you have 2.4 minutes per question. Gas piping sizing problems and offset calculations can each consume 4–5 minutes if you are unfamiliar with the tables. Burning time on early hard questions leaves no margin for later ones.

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