CO Journeyman Plumber Exam
Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A| Instant Download Pdf
1. What is the standard slope for a 2-inch drain pipe for proper drainage?
A. 1/8 inch per foot
B. 1/4 inch per foot
C. 1/2 inch per foot
D. 1 inch per foot
B. 1/4 inch per foot
Rationale: A 1/4 inch per foot slope ensures proper gravity flow
without causing blockages or excessive velocity.
2. Which type of valve is best for isolating water to a specific fixture?
A. Ball valve
B. Gate valve
C. Globe valve
D. Check valve
A. Ball valve
Rationale: Ball valves allow quick shut-off for individual fixtures
with minimal pressure drop.
3. What is the maximum number of fixture units allowed on a 3-inch
horizontal drain pipe?
A. 30
B. 40
C. 50
D. 60
C. 50
Rationale: Plumbing codes specify maximum fixture units per pipe
size to ensure adequate drainage.
,4. What type of fitting is used to connect pipes of different diameters?
A. Elbow
B. Reducer
C. Coupling
D. Tee
B. Reducer
Rationale: Reducers are designed specifically to connect pipes of
different diameters while maintaining flow.
5. Which material is commonly used for underground water service lines?
A. Copper
B. PVC
C. Galvanized steel
D. CPVC
B. PVC
Rationale: PVC is resistant to corrosion and easy to install
underground.
6. What is the purpose of a vent in a plumbing system?
A. To remove wastewater
B. To provide water pressure
C. To prevent sewer gas from entering the building
D. To measure flow rate
C. To prevent sewer gas from entering the building
Rationale: Vents allow air to enter the drainage system, preventing
siphoning and sewer gas buildup.
7. Which type of pipe is most suitable for high-temperature water supply?
A. PVC
B. CPVC
C. ABS
D. PEX
B. CPVC
Rationale: CPVC can handle higher temperatures than standard
PVC and is approved for hot water.
8. How far above the floor should a water closet (toilet) be installed for
standard residential use?
A. 12 inches
B. 15 inches
C. 17 inches
, D. 20 inches
C. 17 inches
Rationale: Standard residential toilets are installed at 17 inches from
floor to seat for comfort and code compliance.
9. What is the main purpose of a trap in plumbing?
A. To filter debris
B. To prevent odors from entering the building
C. To regulate water pressure
D. To connect two pipes
B. To prevent odors from entering the building
Rationale: Traps hold a water seal that blocks sewer gases from
entering occupied spaces.
10. How many inches should a lavatory drain line be from the
finished floor to the trap weir?
A. 12 inches
B. 15 inches
C. 18 inches
D. 20 inches
B. 15 inches
Rationale: Plumbing codes specify trap heights for proper drainage
and fixture compatibility.
11. Which tool is used to bend copper tubing without collapsing it?
A. Pipe wrench
B. Tube bender
C. Hacksaw
D. Reamer
B. Tube bender
Rationale: Tube benders create smooth bends in copper tubing
without kinking or collapsing.
12. What type of fitting is used to change the direction of a pipe by
90 degrees?
A. Tee
B. Coupling
C. Elbow
D. Reducer
C. Elbow
Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A| Instant Download Pdf
1. What is the standard slope for a 2-inch drain pipe for proper drainage?
A. 1/8 inch per foot
B. 1/4 inch per foot
C. 1/2 inch per foot
D. 1 inch per foot
B. 1/4 inch per foot
Rationale: A 1/4 inch per foot slope ensures proper gravity flow
without causing blockages or excessive velocity.
2. Which type of valve is best for isolating water to a specific fixture?
A. Ball valve
B. Gate valve
C. Globe valve
D. Check valve
A. Ball valve
Rationale: Ball valves allow quick shut-off for individual fixtures
with minimal pressure drop.
3. What is the maximum number of fixture units allowed on a 3-inch
horizontal drain pipe?
A. 30
B. 40
C. 50
D. 60
C. 50
Rationale: Plumbing codes specify maximum fixture units per pipe
size to ensure adequate drainage.
,4. What type of fitting is used to connect pipes of different diameters?
A. Elbow
B. Reducer
C. Coupling
D. Tee
B. Reducer
Rationale: Reducers are designed specifically to connect pipes of
different diameters while maintaining flow.
5. Which material is commonly used for underground water service lines?
A. Copper
B. PVC
C. Galvanized steel
D. CPVC
B. PVC
Rationale: PVC is resistant to corrosion and easy to install
underground.
6. What is the purpose of a vent in a plumbing system?
A. To remove wastewater
B. To provide water pressure
C. To prevent sewer gas from entering the building
D. To measure flow rate
C. To prevent sewer gas from entering the building
Rationale: Vents allow air to enter the drainage system, preventing
siphoning and sewer gas buildup.
7. Which type of pipe is most suitable for high-temperature water supply?
A. PVC
B. CPVC
C. ABS
D. PEX
B. CPVC
Rationale: CPVC can handle higher temperatures than standard
PVC and is approved for hot water.
8. How far above the floor should a water closet (toilet) be installed for
standard residential use?
A. 12 inches
B. 15 inches
C. 17 inches
, D. 20 inches
C. 17 inches
Rationale: Standard residential toilets are installed at 17 inches from
floor to seat for comfort and code compliance.
9. What is the main purpose of a trap in plumbing?
A. To filter debris
B. To prevent odors from entering the building
C. To regulate water pressure
D. To connect two pipes
B. To prevent odors from entering the building
Rationale: Traps hold a water seal that blocks sewer gases from
entering occupied spaces.
10. How many inches should a lavatory drain line be from the
finished floor to the trap weir?
A. 12 inches
B. 15 inches
C. 18 inches
D. 20 inches
B. 15 inches
Rationale: Plumbing codes specify trap heights for proper drainage
and fixture compatibility.
11. Which tool is used to bend copper tubing without collapsing it?
A. Pipe wrench
B. Tube bender
C. Hacksaw
D. Reamer
B. Tube bender
Rationale: Tube benders create smooth bends in copper tubing
without kinking or collapsing.
12. What type of fitting is used to change the direction of a pipe by
90 degrees?
A. Tee
B. Coupling
C. Elbow
D. Reducer
C. Elbow
