D1 & D2 Water Distribution Exam Prep – Practice
Questions & Answers | Latest Update 2026 | Graded A+
The only absolutely reliable method of backflow prevention is the use of - correct
answerAir Gap
The bubbles formed in a positive multiple tube fermentation test are - correct
answerCarbon Dioxide
The maximum rate of withdrawal of gas from a 150lb chlorine cylinder in 24-hours is -
correct answer40 lbs
If you encounter a liquid chlorine leak in a one tone container, what action should you
take first, to reduce the severity of the leak? - correct answerRotate the container to
place the leak at the top
The most commonly used water disinfectant in the United States is - correct
answerChlorine
When collecting a distribution system sample, the water should be allowed to run for a
period of time prior to sample collection. How long - correct answerAs long as
necessary to permit cleaning of service line
Sample bottles wich are furnished by a certified laboratory for collection of
bacteriological samples - correct answerAre ready to use
The difference between water pressure upstream and downstream of a pump when it is
not in operations is know as the - correct answerTotal static head
A device that automatically shuts off flow in an elevated storage tank when the water
level in the tank reache a preset level is termed a - correct answerAltitude valve
In an occupied trench requiring personal egress what is the maximum allowable
distance between a worker and an exit letter - correct answer25 feet
A water bearing formation in the soil is referred to as - correct answerAn aquifer
The distance between the static water level and the pumping water level is termed the -
correct answerDrawdown
To prevent the entry of surface contamination into a well is the purpose of - correct
answerSanitary seal
The presence of coliform bacteria in a distribution system - correct answerIndicates that
pathogenic organisms may be present also
,The most common valve type in water distribution system is the - correct answerGate
valve
A Venturi is a device used to - correct answerMeasure water flow
Backspin is occurring after well shut down this indicates - correct answerA faulty check
valve
A ph reading of 6.0 units indicates the water sample is - correct answerSlightly acidic
Chlorine gas - correct answerIs heavier than air
The change in what're demand during the course of a day is called - correct
answerDiurnal variation
Catholic protection is a system used for - correct answerMetallic corrosion inhibition
The elevation of the free surface in a water table well wich is not running is called -
correct answerStatic water level
The maximum momentary load placed on a water supply system is known as - correct
answerPeak demand
Most below ground level storage tanks are constructed of - correct answerConcrete
Hey bacteriological sampling bottle should be - correct answerFilled carefully to leave a
small air space
When fully open, wich of the following will have the lowest friction loss - correct
answerGate valve
Enclosed, open, and smi closed are terms used for the designation and selection of -
correct answerImpellers
The process by wich water changes from the gas to the liquid form is called - correct
answerCondensation
Sleeve type and victaulic couplings are the most common forms of - correct
answerMechanical couplings
The most commonly used meter on a small diameter domestic service is the - correct
answerMutating disc meter
If a pump sounds like it's pumping rocks, the most likecly cause is - correct
answerCavitation
, "Backflow Device" is termedused to describe a device that - correct answerPrevents
back flow of potentially contaminated source in to drinking water
Which is a devices used to measure flow - correct answerWeir
When closing a hydrant, it should be - correct answerClosed slowly to reduce surges
A bacteriological test that measures only the presence or absence of Califorms is -
correct answerColilert
A compound meter is a device which - correct answerProvides accurate reading over a
wide range of flows
The rotating element in a centrifugal pump is commonly called the - correct
answerImpeller
The packing gland serves many functions in a centrifugal pump. Among these is -
correct answerKeep gritty material from entering the packing box
What are the names of positive displacement pumps - correct answerReciprocating and
rotary
What is the practical maximum suction lift for a centrifugal pump in good working
condition - correct answer15 to 25 feet
Residual chlorine refers to - correct answerThe amount of chlorine in the chlorinated
water after a selected time
The lowest point of the inside of a pipe is known as the - correct answerInvert
If possible why should a main water leak be repaired under pressure - correct answerTo
prevent contamination of the water line
A connection made in to a main that is full or under pressure is called a - correct
answerWet tap
Shoring is normally required for trenches of that minimum depth - correct answer5 feet
Standard first aid procedures direct that the first step to control bleeding is to - correct
answerApply pressure directly to the wound
First aid for a first degree burn is to - correct answerSubmerge the burned area in cold
water
Chlorine leak can be detected by - correct answerApplying ammonia vapor
Questions & Answers | Latest Update 2026 | Graded A+
The only absolutely reliable method of backflow prevention is the use of - correct
answerAir Gap
The bubbles formed in a positive multiple tube fermentation test are - correct
answerCarbon Dioxide
The maximum rate of withdrawal of gas from a 150lb chlorine cylinder in 24-hours is -
correct answer40 lbs
If you encounter a liquid chlorine leak in a one tone container, what action should you
take first, to reduce the severity of the leak? - correct answerRotate the container to
place the leak at the top
The most commonly used water disinfectant in the United States is - correct
answerChlorine
When collecting a distribution system sample, the water should be allowed to run for a
period of time prior to sample collection. How long - correct answerAs long as
necessary to permit cleaning of service line
Sample bottles wich are furnished by a certified laboratory for collection of
bacteriological samples - correct answerAre ready to use
The difference between water pressure upstream and downstream of a pump when it is
not in operations is know as the - correct answerTotal static head
A device that automatically shuts off flow in an elevated storage tank when the water
level in the tank reache a preset level is termed a - correct answerAltitude valve
In an occupied trench requiring personal egress what is the maximum allowable
distance between a worker and an exit letter - correct answer25 feet
A water bearing formation in the soil is referred to as - correct answerAn aquifer
The distance between the static water level and the pumping water level is termed the -
correct answerDrawdown
To prevent the entry of surface contamination into a well is the purpose of - correct
answerSanitary seal
The presence of coliform bacteria in a distribution system - correct answerIndicates that
pathogenic organisms may be present also
,The most common valve type in water distribution system is the - correct answerGate
valve
A Venturi is a device used to - correct answerMeasure water flow
Backspin is occurring after well shut down this indicates - correct answerA faulty check
valve
A ph reading of 6.0 units indicates the water sample is - correct answerSlightly acidic
Chlorine gas - correct answerIs heavier than air
The change in what're demand during the course of a day is called - correct
answerDiurnal variation
Catholic protection is a system used for - correct answerMetallic corrosion inhibition
The elevation of the free surface in a water table well wich is not running is called -
correct answerStatic water level
The maximum momentary load placed on a water supply system is known as - correct
answerPeak demand
Most below ground level storage tanks are constructed of - correct answerConcrete
Hey bacteriological sampling bottle should be - correct answerFilled carefully to leave a
small air space
When fully open, wich of the following will have the lowest friction loss - correct
answerGate valve
Enclosed, open, and smi closed are terms used for the designation and selection of -
correct answerImpellers
The process by wich water changes from the gas to the liquid form is called - correct
answerCondensation
Sleeve type and victaulic couplings are the most common forms of - correct
answerMechanical couplings
The most commonly used meter on a small diameter domestic service is the - correct
answerMutating disc meter
If a pump sounds like it's pumping rocks, the most likecly cause is - correct
answerCavitation
, "Backflow Device" is termedused to describe a device that - correct answerPrevents
back flow of potentially contaminated source in to drinking water
Which is a devices used to measure flow - correct answerWeir
When closing a hydrant, it should be - correct answerClosed slowly to reduce surges
A bacteriological test that measures only the presence or absence of Califorms is -
correct answerColilert
A compound meter is a device which - correct answerProvides accurate reading over a
wide range of flows
The rotating element in a centrifugal pump is commonly called the - correct
answerImpeller
The packing gland serves many functions in a centrifugal pump. Among these is -
correct answerKeep gritty material from entering the packing box
What are the names of positive displacement pumps - correct answerReciprocating and
rotary
What is the practical maximum suction lift for a centrifugal pump in good working
condition - correct answer15 to 25 feet
Residual chlorine refers to - correct answerThe amount of chlorine in the chlorinated
water after a selected time
The lowest point of the inside of a pipe is known as the - correct answerInvert
If possible why should a main water leak be repaired under pressure - correct answerTo
prevent contamination of the water line
A connection made in to a main that is full or under pressure is called a - correct
answerWet tap
Shoring is normally required for trenches of that minimum depth - correct answer5 feet
Standard first aid procedures direct that the first step to control bleeding is to - correct
answerApply pressure directly to the wound
First aid for a first degree burn is to - correct answerSubmerge the burned area in cold
water
Chlorine leak can be detected by - correct answerApplying ammonia vapor
