Colorado Master Plumber Exam Verified
Questions, Correct Answers, and Detailed
Explanations for Science Students||Already
Graded A+
1. What is the minimum water pressure required at the entry to a
residential plumbing system in Colorado?
A. 20 psi
B. 30 psi
C. 40 psi
D. 50 psi
The minimum pressure ensures proper operation of fixtures and
appliances throughout the home.
2. When joining copper tubing, what type of fitting is required for a
soldered joint?
A. Compression fitting
B. Sweat (solder) fitting
C. Threaded fitting
D. Push-fit fitting
Solder fittings are specifically designed to allow proper capillary
action and seal when soldered.
3. What is the maximum allowable lead content in potable water
pipes in Colorado?
A. 2%
B. 0.25%
C. 1%
D. 0.5%
Colorado follows federal law limiting lead in drinking water systems
to protect public health.
4. What is the minimum slope for a 4-inch horizontal DWV (drain,
waste, vent) pipe?
,A. 1/16 inch per foot
B. 1/8 inch per foot
C. 1/4 inch per foot
D. 1/2 inch per foot
A 1/4 inch per foot slope ensures proper gravity drainage without
causing excessive velocity.
5. In Colorado, how often must a backflow prevention assembly be
tested?
A. Annually
B. Every 2 years
C. Every 5 years
D. Only when installed
Annual testing is required to ensure assemblies function properly and
prevent contamination.
6. What is the minimum size of a water service for a single-family
residence?
A. 1/2 inch
B. 3/4 inch
C. 1 inch
D. 1 1/2 inches
3/4 inch provides sufficient flow for typical residential demand,
according to Colorado plumbing code.
7. What type of pipe is prohibited for underground potable water
systems in Colorado?
A. PVC
B. Galvanized steel
C. HDPE
D. Copper
Galvanized steel is prone to corrosion and is no longer approved for
new underground potable water lines.
, 8. What is the minimum clearance required in front of a water heater
for servicing?
A. 12 inches
B. 30 inches
C. 24 inches
D. 36 inches
Sufficient clearance allows safe access for maintenance, inspection,
and repair.
9. Which type of vent is required to extend above the roof line?
A. Circuit vent
B. Wet vent
C. Relief vent
D. Stack vent
Stack vents terminate above the roof to allow proper air flow and
prevent siphoning of traps.
10. What is the minimum trap arm length for a 2-inch diameter pipe?
A. 12 inches
B. 18 inches
C. 24 inches
D. 30 inches
Trap arm length ensures proper drainage and venting without
creating a siphon effect.
11. What is the maximum allowable temperature for a water heater
in Colorado without mixing valves?
A. 120°F
B. 130°F
C. 140°F
D. 150°F
Temperatures above 140°F can cause scalding, and Colorado
plumbing code may require tempering valves.
Questions, Correct Answers, and Detailed
Explanations for Science Students||Already
Graded A+
1. What is the minimum water pressure required at the entry to a
residential plumbing system in Colorado?
A. 20 psi
B. 30 psi
C. 40 psi
D. 50 psi
The minimum pressure ensures proper operation of fixtures and
appliances throughout the home.
2. When joining copper tubing, what type of fitting is required for a
soldered joint?
A. Compression fitting
B. Sweat (solder) fitting
C. Threaded fitting
D. Push-fit fitting
Solder fittings are specifically designed to allow proper capillary
action and seal when soldered.
3. What is the maximum allowable lead content in potable water
pipes in Colorado?
A. 2%
B. 0.25%
C. 1%
D. 0.5%
Colorado follows federal law limiting lead in drinking water systems
to protect public health.
4. What is the minimum slope for a 4-inch horizontal DWV (drain,
waste, vent) pipe?
,A. 1/16 inch per foot
B. 1/8 inch per foot
C. 1/4 inch per foot
D. 1/2 inch per foot
A 1/4 inch per foot slope ensures proper gravity drainage without
causing excessive velocity.
5. In Colorado, how often must a backflow prevention assembly be
tested?
A. Annually
B. Every 2 years
C. Every 5 years
D. Only when installed
Annual testing is required to ensure assemblies function properly and
prevent contamination.
6. What is the minimum size of a water service for a single-family
residence?
A. 1/2 inch
B. 3/4 inch
C. 1 inch
D. 1 1/2 inches
3/4 inch provides sufficient flow for typical residential demand,
according to Colorado plumbing code.
7. What type of pipe is prohibited for underground potable water
systems in Colorado?
A. PVC
B. Galvanized steel
C. HDPE
D. Copper
Galvanized steel is prone to corrosion and is no longer approved for
new underground potable water lines.
, 8. What is the minimum clearance required in front of a water heater
for servicing?
A. 12 inches
B. 30 inches
C. 24 inches
D. 36 inches
Sufficient clearance allows safe access for maintenance, inspection,
and repair.
9. Which type of vent is required to extend above the roof line?
A. Circuit vent
B. Wet vent
C. Relief vent
D. Stack vent
Stack vents terminate above the roof to allow proper air flow and
prevent siphoning of traps.
10. What is the minimum trap arm length for a 2-inch diameter pipe?
A. 12 inches
B. 18 inches
C. 24 inches
D. 30 inches
Trap arm length ensures proper drainage and venting without
creating a siphon effect.
11. What is the maximum allowable temperature for a water heater
in Colorado without mixing valves?
A. 120°F
B. 130°F
C. 140°F
D. 150°F
Temperatures above 140°F can cause scalding, and Colorado
plumbing code may require tempering valves.
