Arkansas Master Plumber Exam Prep 2026/2027 | 200
Practice Questions & Detailed Answers | Verified
Answers with Rationales | Brand New Version | A+
Graded
1. What is the primary purpose of a plumbing trap in a drainage system?
A) To increase water pressure at the fixture outlet
B) To prevent sewer gases from entering an occupied building
C) To increase the velocity of wastewater flow
D) To reduce the temperature of wastewater before discharge
Answer: B
Rationale: A plumbing trap retains a water seal that blocks sewer gases and odors from entering the
occupied portion of a building while still allowing wastewater to drain .
2. What is the primary function of a plumbing vent system?
A) To supply potable water to fixtures
B) To maintain proper air pressure within the drainage system
C) To increase water temperature for sanitation
D) To filter wastewater before it enters the sewer
Answer: B
Rationale: Venting allows air to enter and leave the drainage system, protecting trap seals and
permitting wastewater to flow properly .
,3. According to the Arkansas Plumbing Code, what is the minimum slope required for a 3inch horizontal
drain pipe carrying wastewater?
A) 1/8 inch per foot
B) 1/4 inch per foot
C) 1/2 inch per foot
D) 1 inch per foot
Answer: B
Rationale: The 2018 Arkansas Plumbing Code requires a minimum slope of 1/4 inch per foot for DWV
pipes 3 inches and larger to ensure proper drainage .
4. In a DWV isometric drawing, which color is most commonly used to identify vent piping?
A) Red
B) Blue
C) Green
D) Yellow
Answer: B
Rationale: The Arkansas Plumbing Code recommends blue for vent lines to distinguish them from drain
lines, which are shown in red .
,5. When sizing a water supply branch pipe using the HazenWilliams equation, which factor represents
the pipe's roughness?
A) Cfactor
B) Kfactor
C) Ffactor
D) Rfactor
Answer: A
Rationale: The Cfactor (HazenWilliams coefficient) quantifies pipe roughness; higher values indicate
smoother pipe material .
6. According to APC Appendix E, a water closet (toilet) is assigned how many fixture units?
A) 1.0
B) 1.5
C) 2.0
D) 3.0
Answer: B
Rationale: The 2018 Arkansas Plumbing Code lists a water closet as 1.5 fixture units for water demand
calculations .
7. What is the minimum trap seal depth required by the Arkansas Plumbing Code?
A) 1 inch
, B) 2 inches
C) 3 inches
D) 4 inches
Answer: B
Rationale: Each fixture trap shall have a liquid seal of not less than 2 inches and not more than 4 inches .
8. Which condition is most likely to cause a trap seal to evaporate?
A) Frequent fixture use
B) An infrequently used floor drain
C) High water pressure
D) Proper venting
Answer: B
Rationale: Water in an infrequently used trap can evaporate, eventually eliminating the protective water
seal .
9. What component can automatically replenish water in a trap?
A) Pressure regulator
B) Trap primer
C) Check valve
D) Vacuum breaker
Practice Questions & Detailed Answers | Verified
Answers with Rationales | Brand New Version | A+
Graded
1. What is the primary purpose of a plumbing trap in a drainage system?
A) To increase water pressure at the fixture outlet
B) To prevent sewer gases from entering an occupied building
C) To increase the velocity of wastewater flow
D) To reduce the temperature of wastewater before discharge
Answer: B
Rationale: A plumbing trap retains a water seal that blocks sewer gases and odors from entering the
occupied portion of a building while still allowing wastewater to drain .
2. What is the primary function of a plumbing vent system?
A) To supply potable water to fixtures
B) To maintain proper air pressure within the drainage system
C) To increase water temperature for sanitation
D) To filter wastewater before it enters the sewer
Answer: B
Rationale: Venting allows air to enter and leave the drainage system, protecting trap seals and
permitting wastewater to flow properly .
,3. According to the Arkansas Plumbing Code, what is the minimum slope required for a 3inch horizontal
drain pipe carrying wastewater?
A) 1/8 inch per foot
B) 1/4 inch per foot
C) 1/2 inch per foot
D) 1 inch per foot
Answer: B
Rationale: The 2018 Arkansas Plumbing Code requires a minimum slope of 1/4 inch per foot for DWV
pipes 3 inches and larger to ensure proper drainage .
4. In a DWV isometric drawing, which color is most commonly used to identify vent piping?
A) Red
B) Blue
C) Green
D) Yellow
Answer: B
Rationale: The Arkansas Plumbing Code recommends blue for vent lines to distinguish them from drain
lines, which are shown in red .
,5. When sizing a water supply branch pipe using the HazenWilliams equation, which factor represents
the pipe's roughness?
A) Cfactor
B) Kfactor
C) Ffactor
D) Rfactor
Answer: A
Rationale: The Cfactor (HazenWilliams coefficient) quantifies pipe roughness; higher values indicate
smoother pipe material .
6. According to APC Appendix E, a water closet (toilet) is assigned how many fixture units?
A) 1.0
B) 1.5
C) 2.0
D) 3.0
Answer: B
Rationale: The 2018 Arkansas Plumbing Code lists a water closet as 1.5 fixture units for water demand
calculations .
7. What is the minimum trap seal depth required by the Arkansas Plumbing Code?
A) 1 inch
, B) 2 inches
C) 3 inches
D) 4 inches
Answer: B
Rationale: Each fixture trap shall have a liquid seal of not less than 2 inches and not more than 4 inches .
8. Which condition is most likely to cause a trap seal to evaporate?
A) Frequent fixture use
B) An infrequently used floor drain
C) High water pressure
D) Proper venting
Answer: B
Rationale: Water in an infrequently used trap can evaporate, eventually eliminating the protective water
seal .
9. What component can automatically replenish water in a trap?
A) Pressure regulator
B) Trap primer
C) Check valve
D) Vacuum breaker
