Page 1 of 35
NORTH CAROLINA WATER DISTRIBUTION C EXAM COMPREHENSIVE
QUESTIONS AND CORRECT ANSWERS LATEST EDITION 2026
Question 1
What is the primary purpose of a public water distribution system?
A) To treat wastewater for disposal
B) To deliver safe drinking water to consumers
C) To store water for agricultural use
D) To generate hydroelectric power
Answer: B
Rationale: The distribution system's primary purpose is to transport potable water safely from
the treatment plant to consumers, including residential, commercial, industrial, and fire
protection uses. It must deliver water that is free of cross-connections with unapproved sources
and other potential contaminants.
Question 2
Which of the following is NOT a component of a public water distribution system?
A) Storage tanks
B) Pump stations
C) Wastewater treatment plant
D) Service lines
Answer: C
Rationale: A wastewater treatment plant is part of the wastewater collection and treatment
system, not the drinking water distribution system. Distribution system components include
pipes, valves, hydrants, service lines, meters, pump stations, and storage tanks.
1|Page
,Page 2 of 35
Question 3
What is the definition of a public water system?
A) Any system that provides water for human consumption to 15 or more service connections
B) Any system that provides water to at least 25 people daily for 60 or more days per year
C) Both A and B
D) Any private well serving a single household
Answer: C
Rationale: A public water system delivers water to customers for human consumption and
serves at least 15 service connections or regularly serves at least 25 people daily for 60 or more
days per year. It must be free of cross-connections with unapproved water sources.
Question 4
Which federal law provides uniform national standards for drinking water quality?
A) Clean Water Act
B) Safe Drinking Water Act
C) Resource Conservation and Recovery Act
D) Clean Air Act
Answer: B
Rationale: The Safe Drinking Water Act (SDWA) provides uniform national standards for drinking
water quality, establishing maximum contaminant levels (MCLs) and treatment requirements for
public water systems.
Question 5
What is the primary function of transmission mains?
A) To carry water directly to individual homes
B) To transport large volumes of water across the system
C) To store water for emergency use
D) To treat water before distribution
Answer: B
Rationale: Transmission mains transport large volumes of water from treatment facilities or
wells to various parts of the distribution system. Distribution pipes carry water to individual
customers and are smaller than transmission mains.
2|Page
,Page 3 of 35
Question 6
Which NC agency is responsible for overseeing water supply use reporting, drought, and
conservation?
A) NC Department of Health and Human Services
B) NCDEQ - Division of Water Resources
C) NC Department of Agriculture
D) NC Utilities Commission
Answer: B
Rationale: The North Carolina Division of Environmental Quality (NCDEQ), Division of Water
Resources, oversees water supply use reporting, drought management, and conservation
programs.
Question 7
What is the minimum operating pressure required in a North Carolina water distribution
system?
A) 10 psi
B) 20 psi
C) 30 psi
D) 50 psi
Answer: B
Rationale: NC distribution systems require a minimum operating pressure of 20 psi at all points
in the system under normal conditions to ensure service reliability and prevent contamination
from backflow or intrusion.
Question 8
What is the primary mission of a water distribution operator?
A) To maximize water sales
B) To furnish a continuous supply of safe drinking water
C) To minimize operational costs
D) To expand the distribution network
Answer: B
Rationale: The most difficult and important part of a water distribution operator's job is to
3|Page
, Page 4 of 35
furnish a continuous supply of safe drinking water to consumers. This requires maintaining
pressure, quality, and reliability throughout the system.
Question 9
What are the two main sources of drinking water?
A) Rivers and lakes only
B) Surface water and groundwater
C) Wells and reservoirs
D) Precipitation and runoff
Answer: B
Rationale: The two main sources of drinking water are surface water (rivers, lakes, reservoirs)
and groundwater (wells, aquifers). Both require treatment before distribution to consumers.
Question 10
What is the primary purpose of a distribution system?
A) To treat water
B) To store water
C) To deliver safe drinking water to consumers
D) To measure water usage
Answer: C
Rationale: The distribution system's main purpose is to transport potable water safely from the
treatment plant to consumers. It ensures water reaches customers while maintaining quality
and pressure.
SECTION 2: DISINFECTION & WATER QUALITY
Questions 11–25
Question 11
What is the primary purpose of chlorination in a water distribution system?
A) To improve the taste of water
B) To disinfect water and provide a residual to protect against microbial contamination
C) To soften the water
D) To remove color from water
4|Page
NORTH CAROLINA WATER DISTRIBUTION C EXAM COMPREHENSIVE
QUESTIONS AND CORRECT ANSWERS LATEST EDITION 2026
Question 1
What is the primary purpose of a public water distribution system?
A) To treat wastewater for disposal
B) To deliver safe drinking water to consumers
C) To store water for agricultural use
D) To generate hydroelectric power
Answer: B
Rationale: The distribution system's primary purpose is to transport potable water safely from
the treatment plant to consumers, including residential, commercial, industrial, and fire
protection uses. It must deliver water that is free of cross-connections with unapproved sources
and other potential contaminants.
Question 2
Which of the following is NOT a component of a public water distribution system?
A) Storage tanks
B) Pump stations
C) Wastewater treatment plant
D) Service lines
Answer: C
Rationale: A wastewater treatment plant is part of the wastewater collection and treatment
system, not the drinking water distribution system. Distribution system components include
pipes, valves, hydrants, service lines, meters, pump stations, and storage tanks.
1|Page
,Page 2 of 35
Question 3
What is the definition of a public water system?
A) Any system that provides water for human consumption to 15 or more service connections
B) Any system that provides water to at least 25 people daily for 60 or more days per year
C) Both A and B
D) Any private well serving a single household
Answer: C
Rationale: A public water system delivers water to customers for human consumption and
serves at least 15 service connections or regularly serves at least 25 people daily for 60 or more
days per year. It must be free of cross-connections with unapproved water sources.
Question 4
Which federal law provides uniform national standards for drinking water quality?
A) Clean Water Act
B) Safe Drinking Water Act
C) Resource Conservation and Recovery Act
D) Clean Air Act
Answer: B
Rationale: The Safe Drinking Water Act (SDWA) provides uniform national standards for drinking
water quality, establishing maximum contaminant levels (MCLs) and treatment requirements for
public water systems.
Question 5
What is the primary function of transmission mains?
A) To carry water directly to individual homes
B) To transport large volumes of water across the system
C) To store water for emergency use
D) To treat water before distribution
Answer: B
Rationale: Transmission mains transport large volumes of water from treatment facilities or
wells to various parts of the distribution system. Distribution pipes carry water to individual
customers and are smaller than transmission mains.
2|Page
,Page 3 of 35
Question 6
Which NC agency is responsible for overseeing water supply use reporting, drought, and
conservation?
A) NC Department of Health and Human Services
B) NCDEQ - Division of Water Resources
C) NC Department of Agriculture
D) NC Utilities Commission
Answer: B
Rationale: The North Carolina Division of Environmental Quality (NCDEQ), Division of Water
Resources, oversees water supply use reporting, drought management, and conservation
programs.
Question 7
What is the minimum operating pressure required in a North Carolina water distribution
system?
A) 10 psi
B) 20 psi
C) 30 psi
D) 50 psi
Answer: B
Rationale: NC distribution systems require a minimum operating pressure of 20 psi at all points
in the system under normal conditions to ensure service reliability and prevent contamination
from backflow or intrusion.
Question 8
What is the primary mission of a water distribution operator?
A) To maximize water sales
B) To furnish a continuous supply of safe drinking water
C) To minimize operational costs
D) To expand the distribution network
Answer: B
Rationale: The most difficult and important part of a water distribution operator's job is to
3|Page
, Page 4 of 35
furnish a continuous supply of safe drinking water to consumers. This requires maintaining
pressure, quality, and reliability throughout the system.
Question 9
What are the two main sources of drinking water?
A) Rivers and lakes only
B) Surface water and groundwater
C) Wells and reservoirs
D) Precipitation and runoff
Answer: B
Rationale: The two main sources of drinking water are surface water (rivers, lakes, reservoirs)
and groundwater (wells, aquifers). Both require treatment before distribution to consumers.
Question 10
What is the primary purpose of a distribution system?
A) To treat water
B) To store water
C) To deliver safe drinking water to consumers
D) To measure water usage
Answer: C
Rationale: The distribution system's main purpose is to transport potable water safely from the
treatment plant to consumers. It ensures water reaches customers while maintaining quality
and pressure.
SECTION 2: DISINFECTION & WATER QUALITY
Questions 11–25
Question 11
What is the primary purpose of chlorination in a water distribution system?
A) To improve the taste of water
B) To disinfect water and provide a residual to protect against microbial contamination
C) To soften the water
D) To remove color from water
4|Page
