COLORADO MASTER PLUMBER – QUESTIONS AND ANSWERS | VERIFIED AND
WELL DETAILED ANSWERS | PLUS RATIONALES | GUARANTEED PASS | LATEST
EXAM UPDATE
Core Domains
Cross-Connection Control and Backflow Prevention
Water Distribution Systems and Sizing Calculations
Sanitary Drainage Systems and Fixture Unit Calculations
Vents, Venting Systems, and Air Admittance Valves
Traps, Interceptors, and Separators
Plumbing Fixtures, Installation Techniques, and Materials
Storm Drainage Systems
Colorado Plumbing Laws, Rules, and Regulations
Introduction
The Colorado Master Plumber examination assesses the competency of experienced
plumbing professionals seeking the highest level of licensure in the state. This
comprehensive assessment evaluates a candidate's mastery of foundational theory,
applied professional knowledge, and critical decision-making skills essential for
supervising plumbing work and ensuring public health protection. The examination
emphasizes real-world application through scenario-based questions requiring the
interpretation of the International Plumbing Code (IPC), the International Fuel Gas
Code (IFGC), and the Rules and Regulations of the Colorado Examining Board of
Plumbers. Candidates must demonstrate proficiency in system design, code
compliance, and ethical professional judgment to obtain a passing score of 75
percent.
,SECTION ONE: QUESTIONS 1–50
1. A master plumber is reviewing plans for a new commercial kitchen. The plans
show a direct connection between the potable water supply and a carbonated
beverage dispenser. According to cross-connection control principles, what is
the minimum required protection for this installation?
A. A double check valve assembly
B. An air gap
C. A reduced pressure principle backflow preventer
D. A pressure vacuum breaker
🟢 Correct Answer: B. An air gap
🔴 Rationale: Carbonated beverage dispensers are classified as a high-hazard
cross-connection due to the potential for carbon dioxide backpressure and
contamination. An air gap provides the highest level of protection against both
back siphonage and backpressure and is the only acceptable method for this
application. A double check valve assembly and pressure vacuum breaker do not
protect against backpressure. A reduced pressure principle backflow preventer
offers excellent protection but is not the minimum required when an air gap is
feasible.
2. During a rough-in inspection, a plumbing inspector notes that a 4-inch
sanitary drainage pipe is supported at intervals of 12 feet. What is the maximum
allowable spacing for this pipe size according to the IPC?
A. 8 feet
B. 10 feet
C. 12 feet
D. 15 feet
,🟢 Correct Answer: B. 10 feet
🔴 Rationale: The International Plumbing Code Table 308.5 specifies maximum
support spacing for PVC and ABS drainage pipe. A 4-inch diameter pipe must be
supported at intervals not exceeding 10 feet. The observed spacing of 12 feet
exceeds the code maximum and constitutes a violation requiring correction.
3. A master plumber is calculating the total drainage fixture units (DFU) for a
residential bathroom group consisting of one water closet, one lavatory, one
bathtub, and one shower. Using standard IPC values, what is the correct total?
A. 6 DFU
B. 8 DFU
C. 10 DFU
D. 12 DFU
🟢 Correct Answer: C. 10 DFU
🔴 Rationale: According to standard IPC fixture unit values, a water closet is 4
DFU, a lavatory is 2 DFU, a bathtub is 2 DFU, and a shower is 2 DFU. The sum is 10
DFU. When sizing a single bathroom group, some code editions permit using a
reduced value, but the individual fixture sum remains 10 DFU.
4. A plumbing contractor loses the services of their responsible master plumber.
Under Colorado Board Rules, how many days does the contractor have to hire a
replacement master plumber before the registration is placed into "Need
Master Hire – Cannot Practice" status?
A. 10 days
B. 20 days
, C. 30 days
D. 45 days
🟢 Correct Answer: B. 20 days
🔴 Rationale: Colorado Board Rule 6.2 explicitly allows a plumbing contractor
twenty days to hire another master plumber after losing the services of the
responsible master. Failure to hire within this period results in the registration
being placed into "Need Master Hire – Cannot Practice" status until a master is
hired and the appropriate fee is paid.
5. A master plumber is installing a water service line in an area with a local frost
depth of 36 inches. What is the minimum required burial depth for the pipe to
prevent freezing?
A. 24 inches
B. 36 inches
C. 42 inches
D. 48 inches
🟢 Correct Answer: B. 36 inches
🔴 Rationale: The water service pipe must be buried below the local frost line to
prevent freezing. If the local frost depth is 36 inches, the pipe must be buried at
least 36 inches deep. Some local codes may require additional depth for
protection from frost heave, but the minimum standard is the frost line depth
itself.
6. During an inspection of a high-rise building, a master plumber observes that
the storm drainage system discharges into the sanitary drainage system. What
WELL DETAILED ANSWERS | PLUS RATIONALES | GUARANTEED PASS | LATEST
EXAM UPDATE
Core Domains
Cross-Connection Control and Backflow Prevention
Water Distribution Systems and Sizing Calculations
Sanitary Drainage Systems and Fixture Unit Calculations
Vents, Venting Systems, and Air Admittance Valves
Traps, Interceptors, and Separators
Plumbing Fixtures, Installation Techniques, and Materials
Storm Drainage Systems
Colorado Plumbing Laws, Rules, and Regulations
Introduction
The Colorado Master Plumber examination assesses the competency of experienced
plumbing professionals seeking the highest level of licensure in the state. This
comprehensive assessment evaluates a candidate's mastery of foundational theory,
applied professional knowledge, and critical decision-making skills essential for
supervising plumbing work and ensuring public health protection. The examination
emphasizes real-world application through scenario-based questions requiring the
interpretation of the International Plumbing Code (IPC), the International Fuel Gas
Code (IFGC), and the Rules and Regulations of the Colorado Examining Board of
Plumbers. Candidates must demonstrate proficiency in system design, code
compliance, and ethical professional judgment to obtain a passing score of 75
percent.
,SECTION ONE: QUESTIONS 1–50
1. A master plumber is reviewing plans for a new commercial kitchen. The plans
show a direct connection between the potable water supply and a carbonated
beverage dispenser. According to cross-connection control principles, what is
the minimum required protection for this installation?
A. A double check valve assembly
B. An air gap
C. A reduced pressure principle backflow preventer
D. A pressure vacuum breaker
🟢 Correct Answer: B. An air gap
🔴 Rationale: Carbonated beverage dispensers are classified as a high-hazard
cross-connection due to the potential for carbon dioxide backpressure and
contamination. An air gap provides the highest level of protection against both
back siphonage and backpressure and is the only acceptable method for this
application. A double check valve assembly and pressure vacuum breaker do not
protect against backpressure. A reduced pressure principle backflow preventer
offers excellent protection but is not the minimum required when an air gap is
feasible.
2. During a rough-in inspection, a plumbing inspector notes that a 4-inch
sanitary drainage pipe is supported at intervals of 12 feet. What is the maximum
allowable spacing for this pipe size according to the IPC?
A. 8 feet
B. 10 feet
C. 12 feet
D. 15 feet
,🟢 Correct Answer: B. 10 feet
🔴 Rationale: The International Plumbing Code Table 308.5 specifies maximum
support spacing for PVC and ABS drainage pipe. A 4-inch diameter pipe must be
supported at intervals not exceeding 10 feet. The observed spacing of 12 feet
exceeds the code maximum and constitutes a violation requiring correction.
3. A master plumber is calculating the total drainage fixture units (DFU) for a
residential bathroom group consisting of one water closet, one lavatory, one
bathtub, and one shower. Using standard IPC values, what is the correct total?
A. 6 DFU
B. 8 DFU
C. 10 DFU
D. 12 DFU
🟢 Correct Answer: C. 10 DFU
🔴 Rationale: According to standard IPC fixture unit values, a water closet is 4
DFU, a lavatory is 2 DFU, a bathtub is 2 DFU, and a shower is 2 DFU. The sum is 10
DFU. When sizing a single bathroom group, some code editions permit using a
reduced value, but the individual fixture sum remains 10 DFU.
4. A plumbing contractor loses the services of their responsible master plumber.
Under Colorado Board Rules, how many days does the contractor have to hire a
replacement master plumber before the registration is placed into "Need
Master Hire – Cannot Practice" status?
A. 10 days
B. 20 days
, C. 30 days
D. 45 days
🟢 Correct Answer: B. 20 days
🔴 Rationale: Colorado Board Rule 6.2 explicitly allows a plumbing contractor
twenty days to hire another master plumber after losing the services of the
responsible master. Failure to hire within this period results in the registration
being placed into "Need Master Hire – Cannot Practice" status until a master is
hired and the appropriate fee is paid.
5. A master plumber is installing a water service line in an area with a local frost
depth of 36 inches. What is the minimum required burial depth for the pipe to
prevent freezing?
A. 24 inches
B. 36 inches
C. 42 inches
D. 48 inches
🟢 Correct Answer: B. 36 inches
🔴 Rationale: The water service pipe must be buried below the local frost line to
prevent freezing. If the local frost depth is 36 inches, the pipe must be buried at
least 36 inches deep. Some local codes may require additional depth for
protection from frost heave, but the minimum standard is the frost line depth
itself.
6. During an inspection of a high-rise building, a master plumber observes that
the storm drainage system discharges into the sanitary drainage system. What
