NEW MEXICO JP JOURNEYMAN PLUMBER EXAM COMPLETE
EXAM QUESTIONS AND VERIFIED ANSWERS | 2026–2027
LATEST UPDATE | GUARANTEED PASS | DETAILED
RATIONALES | FULL STUDY GUIDE | EXAM PREP | PRACTICE
TEST | CERTIFICATION PREPARATION
SECTION ONE: QUESTIONS 1–100
1. Under the Uniform Plumbing Code (UPC) adopted by New Mexico, what is the minimum
slope required 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) 1/2 inch per foot
Correct Answer: B) 1/8 inch per foot
Rationale: The UPC requires that 4-inch and larger horizontal drainage pipes maintain a minimum
slope of 1/8 inch per foot to ensure adequate flow velocity and prevent solids from settling. Pipes 3
inches and smaller require a minimum of 1/4 inch per foot. New Mexico enforces these UPC
standards through the Construction Industries Division .
2. What is the minimum trap seal depth required by the UPC?
A) 1 inch
B) 2 inches
C) 3 inches
D) 4 inches
Correct Answer: B) 2 inches
Rationale: The UPC requires trap seals to be not less than 2 inches and not more than 4 inches to
prevent sewer gas from entering the building while maintaining an effective liquid seal. This standard
applies to all plumbing fixtures and is a frequently tested concept on the NM journeyman exam .
3. A cleanout is required at the base of each:
A) Horizontal branch
B) Fixture drain
C) Stack
D) Vent pipe
Correct Answer: C) Stack
Rationale: The UPC mandates that a cleanout must be installed at the base of each soil or waste
stack to provide access for maintenance and removal of blockages. Cleanouts are essential for system
maintenance and are tested heavily on the NM journeyman exam .
4. What is the Drainage Fixture Unit (DFU) value for a standard water closet under the UPC?
A) 2 DFU
, B) 3 DFU
C) 4 DFU
D) 6 DFU
Correct Answer: C) 4 DFU
Rationale: Under the UPC, a standard water closet (toilet) carries a DFU value of 4. This is a critical
value for plumbing system sizing calculations and is a high-yield concept frequently tested on the NM
journeyman exam .
5. What is the minimum size building sewer for a single-family dwelling with water closets?
A) 2 inches
B) 3 inches
C) 4 inches
D) 6 inches
Correct Answer: C) 4 inches
Rationale: The UPC requires a minimum 4-inch building sewer for residential installations when water
closets are connected to the system. This sizing requirement ensures adequate drainage capacity and
is a commonly tested code requirement .
6. The maximum static water pressure permitted within a building under the UPC is:
A) 60 psi
B) 80 psi
C) 100 psi
D) 120 psi
Correct Answer: B) 80 psi
Rationale: The UPC limits maximum static water pressure to 80 psi; a pressure-reducing valve (PRV) is
required when pressure exceeds this limit. This is a critical concept for water supply system design
and is frequently tested .
7. A backflow preventer is required when which condition exists?
A) Water pressure exceeds 60 psi
B) A cross-connection exists
C) Pipe length exceeds 100 feet
D) Water heater capacity exceeds 50 gallons
Correct Answer: B) A cross-connection exists
Rationale: Backflow protection is required wherever a potential cross-connection exists between
potable and non-potable water systems. This is fundamental to protecting the public water supply
and is a core concept tested on the journeyman exam .
8. What is the minimum size pipe for a water service supplying a dwelling under the UPC?
A) 1/2 inch
B) 3/4 inch
C) 1 inch
D) 1-1/4 inches
Correct Answer: B) 3/4 inch
, Rationale: The UPC requires a minimum 3/4-inch water service for residential dwellings. This sizing
ensures adequate water supply for household fixtures and is a fundamental code requirement tested
on the NM journeyman exam .
9. The minimum air gap required for a lavatory faucet above the flood rim is:
A) 1 inch
B) 2 inches
C) 3 inches
D) 4 inches
Correct Answer: A) 1 inch
Rationale: The air gap must be at least 1 inch above the flood rim of the fixture to prevent backflow
contamination. This is a critical backflow prevention measure and frequently appears on the exam .
10. What is the maximum developed length for a 2-inch trap arm under the UPC?
A) 3 feet
B) 5 feet
C) 8 feet
D) 12 feet
Correct Answer: B) 5 feet
Rationale: UPC tables limit a 2-inch trap arm to a maximum developed length of approximately 5 feet
to maintain proper venting and prevent siphonage. This is a frequently tested sizing requirement .
11. An atmospheric vacuum breaker (AVB) is an acceptable backflow prevention device for which
type of hazard?
A) High-hazard cross-connections
B) Low-hazard, non-continuous pressure applications
C) All cross-connections regardless of hazard level
D) Fire sprinkler systems only
Correct Answer: B) Low-hazard, non-continuous pressure applications
Rationale: AVBs are suitable only for low-hazard applications where continuous pressure is not
present. High-hazard situations require more robust devices like Reduced Pressure Zone (RPZ)
assemblies. This distinction is critical for the NM exam .
12. A Reduced Pressure Zone (RPZ) backflow preventer is required for:
A) Residential irrigation systems only
B) Low-hazard cross-connections
C) High-hazard cross-connections
D) All hose bibb connections
Correct Answer: C) High-hazard cross-connections
Rationale: RPZ assemblies provide the highest level of backflow protection and are required for high-
hazard cross-connections where contamination would pose a significant health risk. New Mexico
plumbers must select devices based on hazard classification .
13. What is the minimum size of a lavatory trap under the UPC?
A) 1 inch
B) 1-1/4 inches
EXAM QUESTIONS AND VERIFIED ANSWERS | 2026–2027
LATEST UPDATE | GUARANTEED PASS | DETAILED
RATIONALES | FULL STUDY GUIDE | EXAM PREP | PRACTICE
TEST | CERTIFICATION PREPARATION
SECTION ONE: QUESTIONS 1–100
1. Under the Uniform Plumbing Code (UPC) adopted by New Mexico, what is the minimum
slope required 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) 1/2 inch per foot
Correct Answer: B) 1/8 inch per foot
Rationale: The UPC requires that 4-inch and larger horizontal drainage pipes maintain a minimum
slope of 1/8 inch per foot to ensure adequate flow velocity and prevent solids from settling. Pipes 3
inches and smaller require a minimum of 1/4 inch per foot. New Mexico enforces these UPC
standards through the Construction Industries Division .
2. What is the minimum trap seal depth required by the UPC?
A) 1 inch
B) 2 inches
C) 3 inches
D) 4 inches
Correct Answer: B) 2 inches
Rationale: The UPC requires trap seals to be not less than 2 inches and not more than 4 inches to
prevent sewer gas from entering the building while maintaining an effective liquid seal. This standard
applies to all plumbing fixtures and is a frequently tested concept on the NM journeyman exam .
3. A cleanout is required at the base of each:
A) Horizontal branch
B) Fixture drain
C) Stack
D) Vent pipe
Correct Answer: C) Stack
Rationale: The UPC mandates that a cleanout must be installed at the base of each soil or waste
stack to provide access for maintenance and removal of blockages. Cleanouts are essential for system
maintenance and are tested heavily on the NM journeyman exam .
4. What is the Drainage Fixture Unit (DFU) value for a standard water closet under the UPC?
A) 2 DFU
, B) 3 DFU
C) 4 DFU
D) 6 DFU
Correct Answer: C) 4 DFU
Rationale: Under the UPC, a standard water closet (toilet) carries a DFU value of 4. This is a critical
value for plumbing system sizing calculations and is a high-yield concept frequently tested on the NM
journeyman exam .
5. What is the minimum size building sewer for a single-family dwelling with water closets?
A) 2 inches
B) 3 inches
C) 4 inches
D) 6 inches
Correct Answer: C) 4 inches
Rationale: The UPC requires a minimum 4-inch building sewer for residential installations when water
closets are connected to the system. This sizing requirement ensures adequate drainage capacity and
is a commonly tested code requirement .
6. The maximum static water pressure permitted within a building under the UPC is:
A) 60 psi
B) 80 psi
C) 100 psi
D) 120 psi
Correct Answer: B) 80 psi
Rationale: The UPC limits maximum static water pressure to 80 psi; a pressure-reducing valve (PRV) is
required when pressure exceeds this limit. This is a critical concept for water supply system design
and is frequently tested .
7. A backflow preventer is required when which condition exists?
A) Water pressure exceeds 60 psi
B) A cross-connection exists
C) Pipe length exceeds 100 feet
D) Water heater capacity exceeds 50 gallons
Correct Answer: B) A cross-connection exists
Rationale: Backflow protection is required wherever a potential cross-connection exists between
potable and non-potable water systems. This is fundamental to protecting the public water supply
and is a core concept tested on the journeyman exam .
8. What is the minimum size pipe for a water service supplying a dwelling under the UPC?
A) 1/2 inch
B) 3/4 inch
C) 1 inch
D) 1-1/4 inches
Correct Answer: B) 3/4 inch
, Rationale: The UPC requires a minimum 3/4-inch water service for residential dwellings. This sizing
ensures adequate water supply for household fixtures and is a fundamental code requirement tested
on the NM journeyman exam .
9. The minimum air gap required for a lavatory faucet above the flood rim is:
A) 1 inch
B) 2 inches
C) 3 inches
D) 4 inches
Correct Answer: A) 1 inch
Rationale: The air gap must be at least 1 inch above the flood rim of the fixture to prevent backflow
contamination. This is a critical backflow prevention measure and frequently appears on the exam .
10. What is the maximum developed length for a 2-inch trap arm under the UPC?
A) 3 feet
B) 5 feet
C) 8 feet
D) 12 feet
Correct Answer: B) 5 feet
Rationale: UPC tables limit a 2-inch trap arm to a maximum developed length of approximately 5 feet
to maintain proper venting and prevent siphonage. This is a frequently tested sizing requirement .
11. An atmospheric vacuum breaker (AVB) is an acceptable backflow prevention device for which
type of hazard?
A) High-hazard cross-connections
B) Low-hazard, non-continuous pressure applications
C) All cross-connections regardless of hazard level
D) Fire sprinkler systems only
Correct Answer: B) Low-hazard, non-continuous pressure applications
Rationale: AVBs are suitable only for low-hazard applications where continuous pressure is not
present. High-hazard situations require more robust devices like Reduced Pressure Zone (RPZ)
assemblies. This distinction is critical for the NM exam .
12. A Reduced Pressure Zone (RPZ) backflow preventer is required for:
A) Residential irrigation systems only
B) Low-hazard cross-connections
C) High-hazard cross-connections
D) All hose bibb connections
Correct Answer: C) High-hazard cross-connections
Rationale: RPZ assemblies provide the highest level of backflow protection and are required for high-
hazard cross-connections where contamination would pose a significant health risk. New Mexico
plumbers must select devices based on hazard classification .
13. What is the minimum size of a lavatory trap under the UPC?
A) 1 inch
B) 1-1/4 inches
