Page 1 of 182
Minneapolis Journeyman Plumber with
Gas - 498-MN-MI Contractor Exam Newest
2026 Questions with Answers &
Rationales | Instant Pdf Download.
Overview . Plumbing – General
Knowledge (12%) o Understanding of
plumbing systems and components. o
Knowledge o
Question 1
What is the minimum size of a building drain serving a single-
family home under the Minnesota Plumbing Code?
,Page 2 of 182
A) 2 inches
B) 3 inches
C) 4 inches
D) 6 inches
Correct Answer: B) 3 inches
Rationale: The Minnesota Plumbing Code requires a minimum 3-
inch building drain for residential dwellings to ensure adequate
flow capacity and reduce the risk of blockages from solid waste.
A 2-inch drain would be insufficient for toilet waste .
Question 2
Which type of pipe is NOT approved for underground use within
a building in Minnesota?
A) Schedule 40 PVC
B) Cast iron (service weight)
,Page 3 of 182
C) Galvanized steel
D) Type L copper
Correct Answer: C) Galvanized steel
Rationale: Galvanized steel is prohibited for underground use
due to rapid corrosion and scaling when exposed to soil moisture
and chemicals, which leads to flow restriction and eventual pipe
failure .
Question 3
A fixture trap must be installed to prevent siphonage. What is
the maximum allowable trap seal loss?
A) 1 inch
B) 2 inches
C) 3 inches
D) 4 inches
, Page 4 of 182
Correct Answer: A) 1 inch
Rationale: Plumbing codes specify that a trap shall not lose its
water seal by more than 1 inch of water depth due to siphonage
or backpressure. The minimum required seal depth is 2 inches, so
a 1-inch loss maintains protection .
Question 4
What is the minimum vertical distance from the trap weir to the
vent opening for a fixture drain?
A) 2 inches
B) 4 inches
C) 6 inches
D) Twice the pipe diameter
Correct Answer: D) Twice the pipe diameter
Minneapolis Journeyman Plumber with
Gas - 498-MN-MI Contractor Exam Newest
2026 Questions with Answers &
Rationales | Instant Pdf Download.
Overview . Plumbing – General
Knowledge (12%) o Understanding of
plumbing systems and components. o
Knowledge o
Question 1
What is the minimum size of a building drain serving a single-
family home under the Minnesota Plumbing Code?
,Page 2 of 182
A) 2 inches
B) 3 inches
C) 4 inches
D) 6 inches
Correct Answer: B) 3 inches
Rationale: The Minnesota Plumbing Code requires a minimum 3-
inch building drain for residential dwellings to ensure adequate
flow capacity and reduce the risk of blockages from solid waste.
A 2-inch drain would be insufficient for toilet waste .
Question 2
Which type of pipe is NOT approved for underground use within
a building in Minnesota?
A) Schedule 40 PVC
B) Cast iron (service weight)
,Page 3 of 182
C) Galvanized steel
D) Type L copper
Correct Answer: C) Galvanized steel
Rationale: Galvanized steel is prohibited for underground use
due to rapid corrosion and scaling when exposed to soil moisture
and chemicals, which leads to flow restriction and eventual pipe
failure .
Question 3
A fixture trap must be installed to prevent siphonage. What is
the maximum allowable trap seal loss?
A) 1 inch
B) 2 inches
C) 3 inches
D) 4 inches
, Page 4 of 182
Correct Answer: A) 1 inch
Rationale: Plumbing codes specify that a trap shall not lose its
water seal by more than 1 inch of water depth due to siphonage
or backpressure. The minimum required seal depth is 2 inches, so
a 1-inch loss maintains protection .
Question 4
What is the minimum vertical distance from the trap weir to the
vent opening for a fixture drain?
A) 2 inches
B) 4 inches
C) 6 inches
D) Twice the pipe diameter
Correct Answer: D) Twice the pipe diameter
