10 exam-style questions with answers and explanations, straight from our 1,030-question bank. Tap an answer to check yourself. When you're ready, take the scored version in the free practice test.
The MA-MP exam has 120 questions and runs 5 hours 20 minutes.
These 10 free MA-MP questions are organized by exam domain, so you can see how each part of the Massachusetts Master Plumber License Exam blueprint is tested. Reveal the answer and explanation under each question.
Domain 2: Gas Piping, Equipment, and Appliances
Question 1
A substantial new branch is being added to a sound, existing low-pressure natural-gas system. Total connected input after the addition will be 600,000 Btu/h. The new branch can be isolated, and there is no reason to suspect damage elsewhere. With the required inspections and equipment isolation arranged, what is the least extensive compliant piping-test plan?
Show answer & explanation
Correct answer: B - Pressure-test the isolated new branch at 3 psig for 10 minutes, then leak-check the tie-in
Domain 3: Venting
Question 2
During a service call, an atmospheric gas water heater spills flue gases continuously from its draft hood. A carbon monoxide alarm sounds, and two occupants report headache and nausea. What takes priority over further appliance testing?
Show answer & explanation
Correct answer: A - Evacuate everyone outdoors and call 911 from outside
Domain 5: Fixtures, Equipment, and Clearances
Question 3
Before rough inspection, a contractor questions a custom rectangular shower measuring 31 inches wide by 50 inches long at rough-in. Its interior height is 76 inches, and the glass enclosure accommodates a 30-inch circle. This bathroom is not required to be accessible, and no product instructions impose larger dimensions. How should the master plumber resolve the size objection?
Show answer & explanation
Correct answer: D - Retain the dimensions under the rectangular-shower exception
Domain 7: Piping, Valves, and Controls
Question 4
A house has a pressure-reducing valve, a check valve at the water meter, and a potable-water expansion tank. With the water heater off and all fixtures closed, a verified gauge holds at 60 psi for 30 minutes. During a heating cycle, pressure gradually reaches 108 psi; opening a faucet brings it back to 60 psi. Stored water remains at 128°F. Which condition best explains these findings?
Show answer & explanation
Correct answer: C - Inadequate expansion acceptance in the closed water system
Domain 8: Water Supply
Question 5
Potable makeup water supplies a closed process loop containing toxic treatment chemicals. A circulation pump can raise loop pressure above the potable supply pressure, and the makeup connection remains continuously pressurized. Which mechanical backflow-prevention device addresses both the health hazard and the possible reversal of pressure?
Show answer & explanation
Correct answer: B - A reduced-pressure-zone assembly
Domain 10: Drain, Waste, and Vent
Question 6
A proposed 3-inch soil stack has two branch intervals and serves five tank-type water closets, with a total connected load of 20 drainage fixture units. The sizing table lists 48 DFU for a 3-inch stack with one or two branch intervals. The designer concludes that the stack has ample capacity. Which review comment identifies the controlling Massachusetts restriction?
Show answer & explanation
Correct answer: C - Reject the 3-inch stack because it may serve no more than four water closets
Domain 11: Separators, Interceptors, and Grease Traps
Question 7
While reviewing a restaurant drainage plan, a master plumber finds four kitchen waste lines scheduled to pass through the grease interceptor. Under Massachusetts requirements, which discharge must instead bypass the interceptor?
Show answer & explanation
Correct answer: A - A separately trapped commercial food-waste disposer
Domain 13: Isometric Analysis
Question 8
A drainage isometric shows a horizontal building drain flowing from west to east. A horizontal fixture branch approaches from the south at a right angle in plan. The junction must receive the branch without dropping it vertically, and the building drain must continue straight through. Which fitting arrangement properly joins these three pipe ends?
Show answer & explanation
Correct answer: D - A wye and eighth-bend combination directing branch flow east
Domain 14: General Trade Calculations
Question 9
Two parallel pipe runs must be joined with a rolling offset using two 45-degree fittings. Their centerlines are displaced 9 inches horizontally and 12 inches vertically. Each fitting has a 1.50-inch takeout, measured along the diagonal connecting pipe from the fitting centerline intersection to the pipe stop. How long should the straight connecting pipe be cut, to the nearest 0.01 inch?
Show answer & explanation
Correct answer: D - 18.21 inches
Domain 15: Gas Piping
Question 10
A common Schedule 40 steel gas trunk supplies a 90,000-Btu/h boiler and a 45,000-Btu/h water heater. The natural gas has a heating value of 1,000 Btu/ft³ and a specific gravity of 0.60. Inlet pressure is 7 inches w.c.; allowable pressure drop is 0.5 inch w.c. The longest developed path from the meter to any outlet is 66 feet.
For these conditions, the sizing table gives the following capacities in ft³/h, in pipe-size order 1/2, 3/4, 1, and 1-1/4 inches:
60-foot row: 65, 137, 257, 528.
70-foot row: 60, 126, 237, 486.
Using the longest-length method, select the smallest adequate trunk size.