WATER DISTRIBUTION OPERATOR
CERTIFICATION EXAM 2026 WITH VERIFIED
QUESTIONS AND ANSWERS|| GUARANTEED
PASS
How many days will five 150-pound chlorine cylinders last at 5 mg/L applied to
2,000,000 gallons per day? - ANSWER-83.4 days
What is the water level in a 100 ft diameter tank if a pressure gauge at the base
reads 40 psig? - ANSWER-92 feet
How many feet of head are needed to supply 60 psi? - ANSWER-138.6 feet
What is the pressure at the customer if a tank has 20 ft of water and sits 135 ft
above the nearest customer? - ANSWER-67 psi
What is the head pressure in feet if the discharge pressure out of a pump is 92
psi? - ANSWER-212.5 feet
What is the flow in CFS of a pipe 16 inches in diameter flowing at 2,450 gpm? -
ANSWER-5.45 cfs
What is the flow in GPM if a 12-inch diameter pipe is flowing at 2.7 fps? -
ANSWER-951 gpm
,What is the flow-rate in CFS of a square channel 6 ft wide, 4 ft deep, with a
velocity of 3.5 fps? - ANSWER-84 cfs
What is the flow in gallons per minute if a channel is flowing at 5 cfs? -
ANSWER-2,244 gpm
What is the discharge head in feet if a pump discharge pressure indicates 60
psig? - ANSWER-138.6 ft
What is the chlorine demand when the applied dose is 3.0 ppm and the residual
is 2.5 ppm? - ANSWER-0.5 ppm
How many gallons are pumped from a well over 400 minutes at 1,200 gpm? -
ANSWER-480,000 gallons
What is the total force in pounds against a 10-inch diameter gate when upstream
pressure is 110 psig? - ANSWER-8,635 lbs
How many pounds of 65% HTH are needed to disinfect a 12-inch diameter
main, 1,000 ft long at 25 ppm chlorine dose? - ANSWER-1.22 lbs
What is the risk of emptying an underground storage tank when the water table
is high? - ANSWER-The tank might 'float' and damage the tank and
surrounding pipes if emptied when the water table is high.
What is a thrust block? - ANSWER-A thrust block is installed at joints on a
water main where the water flow changes direction to prevent movement.
What is a standpipe? - ANSWER-A standpipe is a cylindrical water reservoir
that is taller than its diameter, used for water storage.
, What is a check valve? - ANSWER-A check valve is a valve located at well
heads and pump stations used to prevent reverse flow of water.
Why paint the interior walls of a water storage tank? - ANSWER-Painting the
interior walls helps to reduce corrosion and prevent lead and copper from
leaching into the water.
What is an advantage of a grid system layout for water mains? - ANSWER-An
advantage of a grid system is that there are no dead-end mains, improving water
flow and system reliability.
What is a clearwell? - ANSWER-A clearwell is a storage vessel for treated
potable water, ensuring it is free of debris.
What is a butterfly valve? - ANSWER-A butterfly valve is a valve with a
restricting element that rotates 90 degrees into and out of its seat.
What are surge tanks used for? - ANSWER-Surge tanks are primarily used to
absorb pressure fluctuations in a water distribution system.
What is the purpose of storing water for short-term emergency use? -
ANSWER-To ensure a reliable supply of water during emergencies or
disruptions in service.
What is water hammer? - ANSWER-A pressure surge caused when a fluid in
motion is forced to stop or change direction suddenly, which can damage
pipelines.
What happens to the maximum chlorine feed rate from a chlorine cylinder as
the temperature decreases? - ANSWER-The maximum chlorine feed rate
decreases.
CERTIFICATION EXAM 2026 WITH VERIFIED
QUESTIONS AND ANSWERS|| GUARANTEED
PASS
How many days will five 150-pound chlorine cylinders last at 5 mg/L applied to
2,000,000 gallons per day? - ANSWER-83.4 days
What is the water level in a 100 ft diameter tank if a pressure gauge at the base
reads 40 psig? - ANSWER-92 feet
How many feet of head are needed to supply 60 psi? - ANSWER-138.6 feet
What is the pressure at the customer if a tank has 20 ft of water and sits 135 ft
above the nearest customer? - ANSWER-67 psi
What is the head pressure in feet if the discharge pressure out of a pump is 92
psi? - ANSWER-212.5 feet
What is the flow in CFS of a pipe 16 inches in diameter flowing at 2,450 gpm? -
ANSWER-5.45 cfs
What is the flow in GPM if a 12-inch diameter pipe is flowing at 2.7 fps? -
ANSWER-951 gpm
,What is the flow-rate in CFS of a square channel 6 ft wide, 4 ft deep, with a
velocity of 3.5 fps? - ANSWER-84 cfs
What is the flow in gallons per minute if a channel is flowing at 5 cfs? -
ANSWER-2,244 gpm
What is the discharge head in feet if a pump discharge pressure indicates 60
psig? - ANSWER-138.6 ft
What is the chlorine demand when the applied dose is 3.0 ppm and the residual
is 2.5 ppm? - ANSWER-0.5 ppm
How many gallons are pumped from a well over 400 minutes at 1,200 gpm? -
ANSWER-480,000 gallons
What is the total force in pounds against a 10-inch diameter gate when upstream
pressure is 110 psig? - ANSWER-8,635 lbs
How many pounds of 65% HTH are needed to disinfect a 12-inch diameter
main, 1,000 ft long at 25 ppm chlorine dose? - ANSWER-1.22 lbs
What is the risk of emptying an underground storage tank when the water table
is high? - ANSWER-The tank might 'float' and damage the tank and
surrounding pipes if emptied when the water table is high.
What is a thrust block? - ANSWER-A thrust block is installed at joints on a
water main where the water flow changes direction to prevent movement.
What is a standpipe? - ANSWER-A standpipe is a cylindrical water reservoir
that is taller than its diameter, used for water storage.
, What is a check valve? - ANSWER-A check valve is a valve located at well
heads and pump stations used to prevent reverse flow of water.
Why paint the interior walls of a water storage tank? - ANSWER-Painting the
interior walls helps to reduce corrosion and prevent lead and copper from
leaching into the water.
What is an advantage of a grid system layout for water mains? - ANSWER-An
advantage of a grid system is that there are no dead-end mains, improving water
flow and system reliability.
What is a clearwell? - ANSWER-A clearwell is a storage vessel for treated
potable water, ensuring it is free of debris.
What is a butterfly valve? - ANSWER-A butterfly valve is a valve with a
restricting element that rotates 90 degrees into and out of its seat.
What are surge tanks used for? - ANSWER-Surge tanks are primarily used to
absorb pressure fluctuations in a water distribution system.
What is the purpose of storing water for short-term emergency use? -
ANSWER-To ensure a reliable supply of water during emergencies or
disruptions in service.
What is water hammer? - ANSWER-A pressure surge caused when a fluid in
motion is forced to stop or change direction suddenly, which can damage
pipelines.
What happens to the maximum chlorine feed rate from a chlorine cylinder as
the temperature decreases? - ANSWER-The maximum chlorine feed rate
decreases.
