CO Journeyman Plumber Exam
Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A
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
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
||
