Plumber’s Exam | Interior Design Professional Exam 2026/2027 Latest Update | Questions And Verified Answers | Graded A+

PLUMBER’S EXAM | INTERIOR DESIGN PROFESSIONAL EXAM
2026/2027 LATEST UPDATE | QUESTIONS AND VERIFIED ANSWERS
| GRADED A+


What is the minimum size of a water meter and service piping in inches for a water supply system of
34 fixture units with a maximum developed length of 200 feet. The water pressure of the system is
35 psi. -
CORRECT|ANSWER

1



Table AP201.1



What is the minimum sized trap that can be used for the drainage system of a bathtub (with or
without shower head and/or whirlpool attachments)? -
CORRECT|ANSWER

1.5



Table P3201.7



A water heater pan drain must extend full-size and terminate over a suitably located indirect waste
receptor or must extend to the exterior of the building and terminate not less than _____ inches and
not more than _____ inches above the adjacent ground surface. -
CORRECT|ANSWER

6, 24



P2801.6.2



A laundry tray waste line is permitted to connect into a standpipe for automatic clothes washer
drain. The standpipe must extend not less than _____ above the trap weir and must extend above
the flood level rim of the laundry tray. -
CORRECT|ANSWER

30 inches (762 mm)



P2706.1.2.1

,Clothes closets, linen closets and pantries not exceeding _____ in area, with the smallest dimension
not greater than 3 feet (915 mm) and having wall and ceiling surfaces of gypsum board will not
require fire sprinklers. -
CORRECT|ANSWER

24 square feet (2.2 m2)



P2904.1.1



If a water closet can be removed to provide cleanout access, does that fulfill the cleanout
requirement of the code? -
CORRECT|ANSWER

No



P3005.2.3



Appliances and equipment used for heating water or storing hot water have to be protected by
_____. -
CORRECT|ANSWER

pressure-relief valve and temperature-relief valve or a combination pressure and temperature-relief
valve.



P2804.1



Where the fixture drains connect at different levels, the common vent must connect as a _____
extension of the _____ drain. -
CORRECT|ANSWER

vertical, vertical



P3107.3



The minimum air gap distance in inches for lavatories and other fixtures with effective opening not
greater than 1/2 inch in diameter that are close to a wall is: -
CORRECT|ANSWER

,1.5



Table P2902.3.1



In areas prone to flooding as established by the code, water supply systems must be designed and
constructed to prevent _____ of floodwaters. -
CORRECT|ANSWER

infiltration



P2602.2



When either a public water-supply or sewer system, or both, are not available, _____, an individual
water-supply or individual sewage-disposal system, or both, must be provided. -
CORRECT|ANSWER

or connection thereto is not feasible



P2602.1



_____ installed in a bathroom are not required to be installed within an enclosure. -
CORRECT|ANSWER

direct-vent water heaters



M2005.2



For water supply systems used predominantly for flush tanks having a water supply fixture unit load
of 12, what is the comparable demand in gallons per minute. -
CORRECT|ANSWER

16.0



Table P2903.6(1)



Test equipment, materials and labor must be furnished by the ______ -

, CORRECT|ANSWER

permittee



P2503.3



The minimum size in inches of a combination waste and vent pipe connecting to a building drain or
building sub drain and serving 31 d.f.u. is _____. -
CORRECT|ANSWER

3



Table 3111.3



The outlet of a water heaters pressure relief valve, temperature relief valve or combination valve,
must be directly connected to the _____. -
CORRECT|ANSWER

none of the above



P2804.6.1



What is the minimum pipe support spacing in feet, required for copper or copper alloy tubing (1 1/4
inch diameter and smaller_ installed in a horizontal orientation. -
CORRECT|ANSWER

6



Table P2605.1



The flow velocity of the water distribution system must be controlled to reduce the possibility of
_____. -
CORRECT|ANSWER

water hammer



P2903.5