COLORADO ICC COMMERCIAL PLUMBING
INSPECTOR EXAM QUESTIONS AND CORRECT
ANSWERS (VERIFIED ANSWERS) Q&A 2026
|INSTANT DOWNLOAD PDF
1. What is the primary purpose of a plumbing inspection?
A. To approve contractor billing
B. To ensure compliance with plumbing codes and safety
standards
C. To increase project costs
D. To design plumbing systems
Rationale: Inspectors verify installations meet adopted codes
for safety, health, and functionality.
Correct Answer: B
2. Which code is most commonly used for commercial
plumbing inspections in Colorado?
A. NEC
B. IPC (International Plumbing Code)
C. IBC Structural Code
D. OSHA Standards
Rationale: The IPC governs plumbing systems in most
jurisdictions adopting ICC codes.
Correct Answer: B
,3. What is the minimum slope for a 4-inch horizontal drainage
pipe?
A. 1/16 inch per foot
B. 1/8 inch per foot
C. 1/4 inch per foot
D. Flat is acceptable
Rationale: IPC typically requires 1/8"–1/4" depending on pipe
size and conditions.
Correct Answer: B
4. What is the purpose of a cleanout?
A. Increase water pressure
B. Provide access for pipe inspection and cleaning
C. Vent sewer gases
D. Reduce pipe diameter
Rationale: Cleanouts allow maintenance access to drainage
systems.
Correct Answer: B
5. What material is prohibited for potable water systems in
most commercial applications?
A. Copper
B. PVC
,C. Lead piping
D. PEX
Rationale: Lead is not allowed due to health hazards.
Correct Answer: C
6. What is the function of a P-trap?
A. Increase flow rate
B. Prevent backflow
C. Block sewer gases from entering buildings
D. Filter solids
Rationale: The trap seal prevents sewer gases from escaping
into occupied spaces.
Correct Answer: C
7. What is required before a plumbing system is concealed?
A. Final payment
B. Pressure or leak test inspection approval
C. Electrical grounding
D. Painting approval
Rationale: Systems must be inspected and approved before
concealment.
Correct Answer: B
, 8. What is the minimum air gap requirement for potable
water protection?
A. Equal to pipe diameter
B. Twice the pipe diameter
C. At least 1 inch or as per code requirement
D. No air gap required
Rationale: Air gaps prevent backflow contamination.
Correct Answer: C
9. What is backflow?
A. Forward water movement
B. Reverse flow of water into potable supply
C. Drain cleaning process
D. Pipe corrosion
Rationale: Backflow can contaminate drinking water systems.
Correct Answer: B
10. Which device prevents backflow in high hazard systems?
A. Ball valve
B. Air chamber
C. Reduced pressure zone (RPZ) assembly
D. Gate valve
INSPECTOR EXAM QUESTIONS AND CORRECT
ANSWERS (VERIFIED ANSWERS) Q&A 2026
|INSTANT DOWNLOAD PDF
1. What is the primary purpose of a plumbing inspection?
A. To approve contractor billing
B. To ensure compliance with plumbing codes and safety
standards
C. To increase project costs
D. To design plumbing systems
Rationale: Inspectors verify installations meet adopted codes
for safety, health, and functionality.
Correct Answer: B
2. Which code is most commonly used for commercial
plumbing inspections in Colorado?
A. NEC
B. IPC (International Plumbing Code)
C. IBC Structural Code
D. OSHA Standards
Rationale: The IPC governs plumbing systems in most
jurisdictions adopting ICC codes.
Correct Answer: B
,3. What is the minimum slope for a 4-inch horizontal drainage
pipe?
A. 1/16 inch per foot
B. 1/8 inch per foot
C. 1/4 inch per foot
D. Flat is acceptable
Rationale: IPC typically requires 1/8"–1/4" depending on pipe
size and conditions.
Correct Answer: B
4. What is the purpose of a cleanout?
A. Increase water pressure
B. Provide access for pipe inspection and cleaning
C. Vent sewer gases
D. Reduce pipe diameter
Rationale: Cleanouts allow maintenance access to drainage
systems.
Correct Answer: B
5. What material is prohibited for potable water systems in
most commercial applications?
A. Copper
B. PVC
,C. Lead piping
D. PEX
Rationale: Lead is not allowed due to health hazards.
Correct Answer: C
6. What is the function of a P-trap?
A. Increase flow rate
B. Prevent backflow
C. Block sewer gases from entering buildings
D. Filter solids
Rationale: The trap seal prevents sewer gases from escaping
into occupied spaces.
Correct Answer: C
7. What is required before a plumbing system is concealed?
A. Final payment
B. Pressure or leak test inspection approval
C. Electrical grounding
D. Painting approval
Rationale: Systems must be inspected and approved before
concealment.
Correct Answer: B
, 8. What is the minimum air gap requirement for potable
water protection?
A. Equal to pipe diameter
B. Twice the pipe diameter
C. At least 1 inch or as per code requirement
D. No air gap required
Rationale: Air gaps prevent backflow contamination.
Correct Answer: C
9. What is backflow?
A. Forward water movement
B. Reverse flow of water into potable supply
C. Drain cleaning process
D. Pipe corrosion
Rationale: Backflow can contaminate drinking water systems.
Correct Answer: B
10. Which device prevents backflow in high hazard systems?
A. Ball valve
B. Air chamber
C. Reduced pressure zone (RPZ) assembly
D. Gate valve
