d d d
Practice Questions And Correct Answers (V
d d d d d
erified Answers) Plus Rationales 2026|202
d d d d
7 Q&A | Instant Download Pdf
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1. The minimum size water service pipe allowed for a single-
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family dwelling is: d d
A. ½ inch d
B. ¾ inch d
C. 1 inch d
D. 1 ¼ inch d d
¾ inch
d
Rationale: Most plumbing codes, including Ohio, set ¾ inch as the minimu
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m water service size for adequate flow and pressure.
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2. A plumbing vent must terminate how far above the roof?
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A. 4 inches d
B. 6 inches d
, C. 8 inches
d
D. 6 inches minimum
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6 inches minimum
d d
Rationale: Vents must extend at least 6 inches above the roof surface t
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o prevent blockages from snow and debris.
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3. The minimum slope for horizontal drainage piping smaller than 4 i
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nches is: d
A. 1/8 inch per foot d d d
B. 1/4 inch per foot d d d
C. 3/8 inch per foot d d d
D. 1/2 inch per foot d d d
1/4 inch per foot
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Rationale: Codes require ¼ inch per foot slope for pipes less than 4 inch
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es to maintain proper flow and prevent clogging.
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4. The maximum vertical distance between a trap and its vent is:
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A. 2 feet d
B. 4 feet d
C. 6 feet d
D. 10 feet d
6 feet
d
Rationale: Code limits trap-to- d d d
vent distance to 6 feet for typical fixture drains to avoid siphoning.
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,5. A cleanout must be installed at every change of direction greater than:
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A. 30 degrees d
B. 45 degrees d
C. 90 degrees d
D. 180 degrees d
90 degrees
d
Rationale: Cleanouts are required at changes of direction of 90 degree
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s or more to allow rodding access.
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6. The minimum size trap for a bathtub is:
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A. 1 ¼ inch
d d
B. 1 ½ inch
d d
C. 2 inches
d
D. 2 ½ inchesd d
1 ½ inch
d d
Rationale: Bathtubs require 1½ inch traps for sufficient drainage.
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7. The minimum size vent for a water closet is:
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A. 1 ¼ inch
d d
B. 1 ½ inch
d d
C. 2 inches
d
D. 3 inches d
2 inches
d
Rationale: Toilets require a 2-inch minimum vent size per code.
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, 8. A plumbing vent cannot terminate within how many feet horizontally
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of a building air intake?
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A. 6 feet d
B. 10 feet d
C. 12 feet d
D. 15 feet d
10 feet d
Rationale: Vents must be at least 10 feet away horizontally from air intak
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es to prevent odors from entering buildings.
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9. The minimum depth of a building sewer below grade is:
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A. 12 inches d
B. 18 inches d
C. 24 inches d
D. 30 inches d
12 inches
d
Rationale: Sewers must be buried at least 12 inches to provide frost an
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d mechanical protection.
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10. What is the maximum spacing of supports for horizontal copper t
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ubing (½ inch)? d d
A. 4 feet d
B. 6 feet d
C. 8 feet d
D. 10 feet d