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MAINE MASTER PLUMBER EXAM WITH VERIFIED
ANSWERS DETAILED RATIONALES GRADED A+
Maine Master Plumber Exam
SECTION 1: GENERAL PLUMBING KNOWLEDGE (Questions 1–40)
Question 1. A licensed plumber is planning a new residential plumbing installation in Maine and
must determine which standards govern the installation. Which reference is most important?
A) A manufacturer's sales catalog
B) The 2021 Uniform Plumbing Code as adopted and amended by Maine
C) A local electrical code only
D) A general construction estimating handbook
Answer: B
Rationale: Maine's Plumbers' Examining Board adopted the 2021 UPC as its plumbing
installation standard, subject to Maine-specific amendments and exclusions.
Question 2. What minimum percentage must an applicant generally achieve to pass the Maine
Master Plumber licensing examination?
A) 60 percent
B) 65 percent
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C) 70 percent
D) 75 percent
Answer: D
Rationale: Maine law establishes a minimum passing grade of 75 percent for the Master
Plumber examination.
Question 3. When determining whether a person qualifies for the Maine Master Plumber
examination through journeyman experience, which requirement applies?
A) One year and 500 hours
B) One year and 2,000 hours
C) Two years and 2,000 hours
D) Four years and 4,000 hours
Answer: B
Rationale: Maine lists at least one year with 2,000 hours of plumbing-installation work as a
licensed journeyman plumber as one qualifying pathway.
Question 4. What is the minimum slope required for a 4-inch horizontal drain pipe per the UPC?
A) 1/16 inch per foot
B) 1/8 inch per foot
C) 1/4 inch per foot
D) 1/2 inch per foot
Answer: B
Rationale: Horizontal drainage pipes 4 inches and larger require a minimum slope of 1/8 inch
per foot. Pipes 3 inches or smaller require 1/4 inch per foot minimum slope.
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Question 5. What is the minimum slope required for a 2-inch horizontal drain pipe per the UPC?
A) 1/16 inch per foot
B) 1/8 inch per foot
C) 1/4 inch per foot
D) 1/2 inch per foot
Answer: C
Rationale: Horizontal drainage pipes 3 inches and smaller (including 2-inch) require a minimum
slope of 1/4 inch per foot to maintain adequate flow velocity.
Question 6. Per the UPC, cleanouts in horizontal drains must be installed at intervals not
exceeding what distance?
A) 50 feet
B) 75 feet
C) 100 feet
D) 125 feet
Answer: C
Rationale: Cleanouts must be installed at maximum 100-foot intervals in horizontal drainage
lines. They are also required at changes of direction and at the upper terminal of the building
drain.
Question 7. What is the DFU value for a floor-mounted water closet (1.6 GPF) per the UPC?
A) 2 DFU
B) 3 DFU
C) 4 DFU
D) 6 DFU
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Answer: C
Rationale: Per the UPC fixture unit table, a floor-mounted water closet with a 1.6 GPF rating has
a DFU value of 4.
Question 8. Per the UPC as adopted by Maine, a lavatory has what DFU value?
A) 0.5 DFU
B) 1 DFU
C) 1.5 DFU
D) 2 DFU
Answer: B
Rationale: Per the UPC fixture unit table, a lavatory has a DFU value of 1.
Question 9. What is the minimum building drain size for a system with 200 DFUs per the UPC as
adopted by Maine?
A) 3 inches
B) 4 inches
C) 5 inches
D) 6 inches
Answer: B
Rationale: Per the UPC drainage sizing tables, a 4-inch building drain at 1/8 inch per foot slope
can handle up to approximately 216 DFUs, so 4 inches is adequate for 200 DFUs.
Question 10. A trainee plumber with a minimum of how many hours of work under the
supervision of a master plumber is eligible to take the examination for a master plumber
license?
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MAINE MASTER PLUMBER EXAM WITH VERIFIED
ANSWERS DETAILED RATIONALES GRADED A+
Maine Master Plumber Exam
SECTION 1: GENERAL PLUMBING KNOWLEDGE (Questions 1–40)
Question 1. A licensed plumber is planning a new residential plumbing installation in Maine and
must determine which standards govern the installation. Which reference is most important?
A) A manufacturer's sales catalog
B) The 2021 Uniform Plumbing Code as adopted and amended by Maine
C) A local electrical code only
D) A general construction estimating handbook
Answer: B
Rationale: Maine's Plumbers' Examining Board adopted the 2021 UPC as its plumbing
installation standard, subject to Maine-specific amendments and exclusions.
Question 2. What minimum percentage must an applicant generally achieve to pass the Maine
Master Plumber licensing examination?
A) 60 percent
B) 65 percent
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C) 70 percent
D) 75 percent
Answer: D
Rationale: Maine law establishes a minimum passing grade of 75 percent for the Master
Plumber examination.
Question 3. When determining whether a person qualifies for the Maine Master Plumber
examination through journeyman experience, which requirement applies?
A) One year and 500 hours
B) One year and 2,000 hours
C) Two years and 2,000 hours
D) Four years and 4,000 hours
Answer: B
Rationale: Maine lists at least one year with 2,000 hours of plumbing-installation work as a
licensed journeyman plumber as one qualifying pathway.
Question 4. What is the minimum slope required for a 4-inch horizontal drain pipe per the UPC?
A) 1/16 inch per foot
B) 1/8 inch per foot
C) 1/4 inch per foot
D) 1/2 inch per foot
Answer: B
Rationale: Horizontal drainage pipes 4 inches and larger require a minimum slope of 1/8 inch
per foot. Pipes 3 inches or smaller require 1/4 inch per foot minimum slope.
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Question 5. What is the minimum slope required for a 2-inch horizontal drain pipe per the UPC?
A) 1/16 inch per foot
B) 1/8 inch per foot
C) 1/4 inch per foot
D) 1/2 inch per foot
Answer: C
Rationale: Horizontal drainage pipes 3 inches and smaller (including 2-inch) require a minimum
slope of 1/4 inch per foot to maintain adequate flow velocity.
Question 6. Per the UPC, cleanouts in horizontal drains must be installed at intervals not
exceeding what distance?
A) 50 feet
B) 75 feet
C) 100 feet
D) 125 feet
Answer: C
Rationale: Cleanouts must be installed at maximum 100-foot intervals in horizontal drainage
lines. They are also required at changes of direction and at the upper terminal of the building
drain.
Question 7. What is the DFU value for a floor-mounted water closet (1.6 GPF) per the UPC?
A) 2 DFU
B) 3 DFU
C) 4 DFU
D) 6 DFU
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Answer: C
Rationale: Per the UPC fixture unit table, a floor-mounted water closet with a 1.6 GPF rating has
a DFU value of 4.
Question 8. Per the UPC as adopted by Maine, a lavatory has what DFU value?
A) 0.5 DFU
B) 1 DFU
C) 1.5 DFU
D) 2 DFU
Answer: B
Rationale: Per the UPC fixture unit table, a lavatory has a DFU value of 1.
Question 9. What is the minimum building drain size for a system with 200 DFUs per the UPC as
adopted by Maine?
A) 3 inches
B) 4 inches
C) 5 inches
D) 6 inches
Answer: B
Rationale: Per the UPC drainage sizing tables, a 4-inch building drain at 1/8 inch per foot slope
can handle up to approximately 216 DFUs, so 4 inches is adequate for 200 DFUs.
Question 10. A trainee plumber with a minimum of how many hours of work under the
supervision of a master plumber is eligible to take the examination for a master plumber
license?
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