Missouri Plumbing Plans Examiner
Exam Practice Questions And Correct
Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant
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1. A plumbing plans examiner reviewing a drainage system primarily
evaluates which aspect of the design?
A. Pipe color coding
B. Hydraulic capacity and code compliance
C. Contractor licensing status
D. Brand of fixtures used
B. Hydraulic capacity and code compliance
The primary responsibility of a plans examiner is to ensure that
drainage systems are properly sized, hydraulically adequate, and
compliant with applicable plumbing codes rather than focusing on
cosmetic or administrative details.
,2. Which document is most critical for determining minimum plumbing
fixture requirements in a building plan?
A. Electrical code manual
B. Mechanical equipment schedule
C. Plumbing code fixture tables
D. Architectural rendering
C. Plumbing code fixture tables
Fixture requirements are determined using plumbing code tables
that specify minimum numbers of fixtures based on occupancy type
and building use.
3. What is the minimum slope typically required for a 4-inch horizontal
sanitary drainage pipe?
A. 1/16 inch per foot
B. 1/8 inch per foot
C. 1/4 inch per foot
D. 1 inch per foot
B. 1/8 inch per foot
Most plumbing codes allow a minimum slope of 1/8 inch per foot for
4-inch horizontal drains to ensure adequate flow velocity and
prevent solids deposition.
4. A plans examiner reviewing vent sizing is primarily concerned with
preventing:
A. Water hammer
, B. Pipe corrosion
C. Trap siphonage and backpressure
D. Excessive water pressure
C. Trap siphonage and backpressure
Vent systems are designed to protect trap seals by preventing
siphonage and backpressure that could allow sewer gases to enter
occupied spaces.
5. Which fixture unit system is commonly used to size drainage piping?
A. British Thermal Units
B. Fixture Unit Values
C. Voltage Units
D. Gallons per second only
B. Fixture Unit Values
Fixture units provide a standardized method for estimating probable
discharge loads to properly size drainage piping systems.
6. Backflow prevention is required primarily to protect against:
A. Pipe freezing
B. Contaminated water entering potable supply
C. Low water pressure
D. Excessive drainage flow
B. Contaminated water entering potable supply
Backflow prevention devices protect the potable water system from
contamination due to reverse flow conditions.
, 7. Which system is designed to carry rainwater from roofs and paved
surfaces?
A. Sanitary system
B. Storm drainage system
C. Vent system
D. Potable water system
B. Storm drainage system
Storm drainage systems are designed specifically to collect and
convey rainwater and surface runoff safely away from structures.
8. A grease interceptor is most commonly required in which occupancy?
A. Residential bedrooms
B. Commercial kitchens
C. Office restrooms
D. Hospital patient rooms
B. Commercial kitchens
Grease interceptors are required in food service establishments to
prevent fats, oils, and grease from entering the drainage system.
9. The purpose of a trap in a plumbing system is to:
A. Increase water pressure
B. Prevent sewer gases from entering buildings
C. Increase pipe velocity
D. Filter solids from wastewater
B. Prevent sewer gases from entering buildings
Exam Practice Questions And Correct
Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant
Download Pdf
1. A plumbing plans examiner reviewing a drainage system primarily
evaluates which aspect of the design?
A. Pipe color coding
B. Hydraulic capacity and code compliance
C. Contractor licensing status
D. Brand of fixtures used
B. Hydraulic capacity and code compliance
The primary responsibility of a plans examiner is to ensure that
drainage systems are properly sized, hydraulically adequate, and
compliant with applicable plumbing codes rather than focusing on
cosmetic or administrative details.
,2. Which document is most critical for determining minimum plumbing
fixture requirements in a building plan?
A. Electrical code manual
B. Mechanical equipment schedule
C. Plumbing code fixture tables
D. Architectural rendering
C. Plumbing code fixture tables
Fixture requirements are determined using plumbing code tables
that specify minimum numbers of fixtures based on occupancy type
and building use.
3. What is the minimum slope typically required for a 4-inch horizontal
sanitary drainage pipe?
A. 1/16 inch per foot
B. 1/8 inch per foot
C. 1/4 inch per foot
D. 1 inch per foot
B. 1/8 inch per foot
Most plumbing codes allow a minimum slope of 1/8 inch per foot for
4-inch horizontal drains to ensure adequate flow velocity and
prevent solids deposition.
4. A plans examiner reviewing vent sizing is primarily concerned with
preventing:
A. Water hammer
, B. Pipe corrosion
C. Trap siphonage and backpressure
D. Excessive water pressure
C. Trap siphonage and backpressure
Vent systems are designed to protect trap seals by preventing
siphonage and backpressure that could allow sewer gases to enter
occupied spaces.
5. Which fixture unit system is commonly used to size drainage piping?
A. British Thermal Units
B. Fixture Unit Values
C. Voltage Units
D. Gallons per second only
B. Fixture Unit Values
Fixture units provide a standardized method for estimating probable
discharge loads to properly size drainage piping systems.
6. Backflow prevention is required primarily to protect against:
A. Pipe freezing
B. Contaminated water entering potable supply
C. Low water pressure
D. Excessive drainage flow
B. Contaminated water entering potable supply
Backflow prevention devices protect the potable water system from
contamination due to reverse flow conditions.
, 7. Which system is designed to carry rainwater from roofs and paved
surfaces?
A. Sanitary system
B. Storm drainage system
C. Vent system
D. Potable water system
B. Storm drainage system
Storm drainage systems are designed specifically to collect and
convey rainwater and surface runoff safely away from structures.
8. A grease interceptor is most commonly required in which occupancy?
A. Residential bedrooms
B. Commercial kitchens
C. Office restrooms
D. Hospital patient rooms
B. Commercial kitchens
Grease interceptors are required in food service establishments to
prevent fats, oils, and grease from entering the drainage system.
9. The purpose of a trap in a plumbing system is to:
A. Increase water pressure
B. Prevent sewer gases from entering buildings
C. Increase pipe velocity
D. Filter solids from wastewater
B. Prevent sewer gases from entering buildings
