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Maryland Master Plumber / Gas Fitter — Practice Exam

What This Practice Exam Covers

This practice exam is built around the Maryland Master Plumber / Gas Fitter licensing exam: 100 questions, 240 minutes, passing score of 70%. You need 70 correct answers to pass.

Two options are available here:

Free practice exam — 10 questions per attempt, pulled from a limited pool. You can retake it as many times as you want. It gives you a feel for question style and difficulty before you commit to anything.

Full practice exam (paid) — 100 questions, timed at 240 minutes, drawn from a pool of 515+ questions. Every attempt pulls a different set, so you won't see the same exam twice. Questions are built directly from the official topic breakdown provided by the exam administrator. If you're serious about passing, this is the tool to use. Start with the free version to get oriented, then move to the full exam for real preparation.

What You'll Be Tested On

Plumbing Fundamentals and Safety — 5 items

These questions test the scope and intent of both the IPC and IFGC, permit and inspection requirements, and code official authority. You need to know defined terms from IFGC Chapter 2, Section 202 — the exam treats definitions as testable content, not background reading. OSHA construction safety is also here: employer responsibilities, accident prevention programs, and jobsite sanitation. Know the specifics under 29 CFR 1926 — potable water requirements under §1926.51(a)(4), toilet facility ratios under §1926.51(c)(1) and §1926.51(c)(3), and washing facility requirements under §1926.51(f)(1) and §1926.51(f)(3)(iii). Permissible exposure limits for airborne contaminants appear under §1926.55(a)(2) and §1926.55(b).

Materials, Uses, and Specifications — 6 items

Know which piping materials are approved and which are prohibited. PVC and CPVC are prohibited for fuel gas. Aluminum is prohibited underground and on exterior applications. CSST, polyethylene, copper, and steel each have specific allowable uses and applicable standards. Pipe identification markings — manufacturer labeling, "Gas" labeling, and spacing intervals — are directly testable. Joint types matter too: threaded, brazed, welded, press-connect, and flared connections each have distinct specifications. Protective coatings and corrosion resistance requirements for metallic piping round out this section.

Traps, Interceptors, and Backwater Valves — 4 items

You need the numbers cold. Trap seal depth, vertical and horizontal distance limits from fixture outlet to trap, and prohibited trap types — bell traps, S-traps, drum traps, crown-vented traps, and moving-part traps — are all fair game. Grease interceptor requirements under IPC Section 1003.3 cover where they're required, sizing, capacity, and prohibited additives. Oil separator design for garages and service stations appears under Section 1003.4. Sand interceptors and clothes washer interceptors are also tested.

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

Minimum fixture counts by occupancy type from IPC Table 403.1 are a reliable exam target. Know clearances, spacing, and securing methods for fixture installation. Standards for specific fixtures — water closets, urinals, lavatories, bathtubs, showers — are tested against sections like IPC 2018, Section 405.3.1, Section 408.3, and Section 412.3. Shower valve temperature-limiting devices and backflow protection at fittings come up here. Water heater installation — location, access, clearances, seismic supports, and drain valves — appears under IPC 2018, Sections 501.3, 502.3, 504.5, and 504.7.

Water Supply Systems — 8 items

Eight questions means this section rewards thorough preparation. Approved pipe materials and joining methods, pressure regulation, booster systems, and water hammer control are all tested. Fixture supply pipe sizing and minimum flow rates appear alongside valve placement requirements from IPC 2018, Sections 606.1 and 606.2. Pressure, head, and volume calculations require you to convert psi to head (and back), calculate tank capacity, and work with pipe capacity ratios. Know the full-open valve and shutoff valve requirements, including Section 606.4 and Section 606.5.1.

Backflow Prevention — 10 items

Ten questions makes this one of the heavier sections. You must know every device type in IPC Table 608.1 — air gap, reduced pressure principle assembly, double check assembly, vacuum breaker, dual check valve — and when each applies. Hazard classification drives device selection: high-hazard contamination versus low-hazard pollution, backpressure versus backsiphonage. Application-specific requirements cover boilers, lawn irrigation, fire sprinkler systems, carbonated beverage dispensers, chemical dispensers, and hose connections. Installation requirements include critical level height, freeze protection, and relief port termination locations.

Drain, Waste, and Vent Systems — 13 items

The largest plumbing section. Drainage fixture unit values from IPC Table 709.1 and 709.2 must be memorized — the exam gives you scenarios and expects you to calculate total DFU loads. Building drain and sewer sizing uses Table 710.1(1) and 710.1(2). Slope requirements for horizontal drainage pipe are in Table 704.1. Cleanout placement intervals and access clearances appear in Sections 708.1.1 through 708.1.9. Vent types, sizing, and developed length requirements draw from Sections 904.2, 905.4, 906.1, 906.2, and 909.3. Indirect waste piping and air gap requirements round out this section.

Special Topics — 3 items

Storm drainage sizing, secondary overflow systems, subsoil drains, and sump pumping. Nonpotable water system requirements — signage, cross-connection protection, storage tank access, venting, and overflow — are covered under IPC Sections 1301.9.6 and 1301.9.10. On-site nonpotable water reuse systems require knowledge of approved sources, prohibited sources, filtration requirements under Section 1303.4, and disinfection under Section 1303.6.

Gas Appliances and Piping — 40 items

Forty questions. This is the exam. Know gas piping materials — steel, copper, CSST, polyethylene — and which tables apply to natural gas versus LP-gas sizing. Pipe sizing from IFGC Appendix A and Appendix D tables requires reading capacity tables correctly, accounting for pressure drop. Testing procedures, pressure requirements, and combustion air calculations are all tested. Venting systems — types, sizing, termination requirements — draw heavily from IFGC Section 503. Appliance installation clearances and prohibited locations appear throughout Section 304, Section 404, and Section 503.

Plumbing Mathematics — 7 items

Fitting allowances for threaded, copper, PVC, and welded pipe. Offset calculations using 45°, 60°, and 22½° constants. Unit conversions between feet, inches, fractions, and decimals. Volume, capacity, and weight calculations for cylindrical containers. Grade, drop, run, and elevation calculations for drainage piping. These are mechanical problems — set them up right and they're straightforward. The resource cited in the question bank is Mathematics for Plumbers and Pipefitters.

Worked Sample Questions

Question 1 — Gas Appliances and Piping

A restaurant owner wants to connect a new commercial range mounted on casters. Which connector type is required?

• A. Semirigid metallic tubing not exceeding 6 feet in length
• B. Standard copper tubing with flared fittings
• C. An appliance connector listed as complying with ANSI Z21.69/CSA 6.16
• D. Corrugated stainless steel tubing (CSST) with standard fittings

Correct Answer: C

Per IFGC Section 411.1.1, commercial cooking appliances on casters — or any appliance moved for cleaning — must connect to the gas piping system with an appliance connector listed to ANSI Z21.69/CSA 6.16. Movement must also be restricted by a restraining device. Options A, B, and D are plausible-sounding traps. The standard listing requirement is what the code actually mandates.

Source: 2018 International Fuel Gas Code (IFGC), Section 411.1.1

Question 2 — Drain, Waste, and Vent Systems

A commercial kitchen DWV system uses combination waste and vent. The owner wants to connect a food waste disposer and a clinical sink to it. Which is correct?

• A. Both may connect
• B. The food waste disposer may connect, but not the clinical sink
• C. Neither may connect
• D. The clinical sink may connect, but not the food waste disposer

Correct Answer: C

IPC Section 915.1 explicitly prohibits both food waste disposer discharge and clinical sink discharge on a combination waste and vent system. No exceptions. Both are named in the code — if you only remember one prohibition, you'll choose B or D and lose the point.

Source: IPC 2018, Section 915.1

Question 3 — Backflow Prevention

Which device is rated for low hazard only and is designed specifically for carbonated beverage machines?

• A. Backflow preventer for carbonated beverage machines conforming to ASSE 1022
• B. Hose connection backflow preventer
• C. Reduced pressure principle backflow prevention assembly
• D. Pressure vacuum breaker assembly

Correct Answer: A

IPC Table 608.1 lists the ASSE 1022 device as rated for low-hazard applications only, protecting against both backpressure and backsiphonage. The reduced pressure principle assembly handles high or low hazard. The pressure vacuum breaker handles backsiphonage only. The hose connection backflow preventer covers high or low hazard. If you try to apply a higher-rated device here and call it equivalent, you'll get the question wrong — the exam asks what is specifically designed for this application.

Source: IPC, Section 608.1, Table 608.1

How to Read Your Score

The passing score is 70% — 70 correct out of 100. Your first practice score is a diagnostic, not a verdict.

If you score below 60%, treat that as a baseline. Identify which topic areas dragged the score down and work those sections first. Gas Appliances and Piping is 40 questions — a weak score there will sink you regardless of how well you do elsewhere.

If you score 60–69%, you're close but not ready. Scoring near the cut line on practice typically means you'll land just under it on the real exam, where question wording is tighter and you can't look anything up. Push for 78–80% on practice before you book your test date.

If you score 75% or above consistently across multiple full-length attempts, your preparation is solid. The 515+ question pool means each attempt draws different questions — consistent performance across attempts is a better signal than one strong run.

Use the topic-by-topic breakdown after each attempt. If Backflow Prevention is costing you points, go back to IPC Table 608.1 and work through every device type. If Plumbing Mathematics is slow, practice the offset and grade calculations until they're automatic.

Where Candidates Lose Points

Gas Appliances and Piping — wrong table or wrong gas type. The IFGC has separate capacity tables for natural gas and LP-gas at different pressures. Candidates pull from the wrong table and get a sizing question completely wrong.

Backflow Prevention — hazard classification errors. Picking a device that works for backsiphonage when the scenario involves backpressure, or applying a high-hazard device when the question asks for the low-hazard-specific answer, are both common mistakes.

DFU calculations — missed fixtures or wrong table. Candidates add up most of the fixtures but miss one, or use Table 709.1 when the question calls for Table 709.2 (or vice versa). A single missed fixture can change a pipe size selection.

Plumbing Mathematics — unit conversion errors. Converting between feet, inches, and decimals mid-calculation and losing track of units. Get the unit conversion habit locked in before exam day.

OSHA sanitation details — imprecise recall. The specific ratios and distances under 29 CFR 1926.51 are tested with precision. "Roughly right" isn't right on this exam.

Running out of time on Gas Appliances. With 40 questions in that topic alone, candidates who slow down on pipe sizing tables can burn the clock and rush the rest of the exam.

Exam Quick Facts