Water Distribution Grade 1 Certification
exam questions and answers elaborated
2025/2026
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What is the general definition of an ion? An _________ with a positive or negative
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charge - CORRECT ANSWER-Atom
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A continuous positive pressure in a distribution system is essential for preventing what
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event? - CORRECT ANSWER-Backflow Event
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_____________ water pressure must be maintained to ensure adequate customer service Il` Il` Il` Il` Il` Il` Il` Il` Il` Il`
during peak flow periods. However, minimum positive pressure must be
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maintained in mains to protect against backflow or backsiphonage from crossconnections. Il` Il` Il` Il` Il` Il` Il` Il` Il` Il`
- CORRECT ANSWER-Minimum
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Name the most common CAUSE for public water supply contamination.
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_________________ or cross-connection - CORRECT ANSWER-Backflow
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Il`
What does a backsiphonage condition usually cause? __________ pressure or
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negative pressure on the service or supply side. - CORRECT ANSWER-Reduced
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What does a double check valve backflow assembly provide effective protection from?
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Both backpressure and backsiphonage of ____________. - CORRECT ANSWER-
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Pollution
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What is equipment that utilizes water for cooling, lubrication, washing or as a solvent
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always susceptible to? - CORRECT ANSWER-Cross-Connection
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What is the difference between a reduced pressure principle backflow device and a
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double check backflow device? The RP has a ______________. - CORRECT
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ANSWER-Relief Valve
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What is the maximum time period between having a backflow device tested by a
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certified backflow tester? ______________ year. - CORRECT ANSWER-1
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What is the regulatory definition of a cross-connection in a water supply? A physical
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connection between a public water system and any source of water or other substance
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that may lead to contamination of the water provided by the _____________ through
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backflow. - CORRECT ANSWER-PWS
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What is the name of a type of valve that reduces the differential pressure across a closed
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disk making the main valve easier to open and close? - CORRECT ANSWERBypass
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Valve
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As soon as Cl2 gas enters the throat area, a victim will sense a sudden stricture in this area-
Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il`
Nature's way of signaling to prevent passage of the gas to the lungs. At this point, the victim
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must attempt to do two things: get out of the area of the leak, proceeding upwind, and to
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take only very short breaths through the mouth. Normal breathing will cause __________,
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which must be prevented if possible. - CORRECT ANSWERCoughing
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, Il`
Chlorine gas causes suffocation, constriction of the chest, tightness in the throat, and
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edema of the ______________. - CORRECT ANSWER-Lungs
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_______________ available chlorine is very effective in killing bacteria. - CORRECT Il`
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ANSWER-Free
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How should an operator store an empty chlorine cylinder? ____________, tagged as
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empty. - CORRECT ANSWER-Upright
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If a chlorine leak occurs, where will chlorine gas accumulate? Near the ____________
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of the tank. - CORRECT ANSWER-Bottom
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What effect does chlorine gas have on the sense of smell? It produces olfactory
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_______________. - CORRECT ANSWER-Fatigue
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What is the primary safety concern when using chlorine gas as opposed to calcium
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hypochlorite or sodium hypochlorite? The potential for a _____________ leak. - Il` Il` Il` Il` Il` Il` Il` Il` Il` Il`
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CORRECT ANSWER-Gas
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What may occur due to chronic exposure to low concentrations of chlorine gas? Chronic
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exposure may cause corrosion of the _____________. - CORRECT ANSWER-Teeth
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What is the process called that changes water vapor to tiny droplets or ice crystals? -
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CORRECT ANSWER-Condensation
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What is the unit of measurement for sound? - CORRECT ANSWER-Decibels
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What happens if grease comes in contact with the winding of a motor? - CORRECT
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ANSWER-The winding insulation my deteriorate.
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What is the most common type of valve used in isolating a small or medium sized
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section of a distribution system? - CORRECT ANSWER-Gate
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What is a possible result of over greasing a bearing? There is extreme _____________ in
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the bearing chamber causing heat and scoring of the shaft. - CORRECT ANSWERFriction
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What is meant by the term "peak demand?" The _____________ momentary load placed
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on a water treatment plant, pumping station or distribution system. - CORRECT
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ANSWER-Maximum
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What is the range of the pH scale? between _____________-14. - CORRECT
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ANSWER-Zero
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What does a Bellows-type sensor reacts to a change in? _________________. -
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CORRECT ANSWER-Pressure
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Centrifugal pumps do not generate suction unless the impeller is submerged in water. If Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il`
a pump is located above the level of water what must be provided on the suction piping
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to hold the prime? - CORRECT ANSWER-Foot Valve
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What causes pump cavitation? A suction line may be ____________ or the pump is above
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the waterline. You have overpumped the well. - CORRECT ANSWER-Clogged
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What does continuous leakage from a mechanical seal on a pump indicate? The
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mechanical seal needs to be ___________________. - CORRECT ANSWER-Replaced
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exam questions and answers elaborated
2025/2026
Il`
What is the general definition of an ion? An _________ with a positive or negative
Il` Il` Il` Il` Il` Il` Il`
Il`
Il` Il` Il` Il` Il` Il` Il` Il`
charge - CORRECT ANSWER-Atom
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Il` Il` Il`
A continuous positive pressure in a distribution system is essential for preventing what
Il` Il` Il` Il` Il` Il` Il`
Il`
Il` Il` Il` Il` Il` Il`
event? - CORRECT ANSWER-Backflow Event
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Il` Il` Il` Il`
_____________ water pressure must be maintained to ensure adequate customer service Il` Il` Il` Il` Il` Il` Il` Il` Il` Il`
during peak flow periods. However, minimum positive pressure must be
Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il`
maintained in mains to protect against backflow or backsiphonage from crossconnections. Il` Il` Il` Il` Il` Il` Il` Il` Il` Il`
- CORRECT ANSWER-Minimum
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Name the most common CAUSE for public water supply contamination.
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_________________ or cross-connection - CORRECT ANSWER-Backflow
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Il`
What does a backsiphonage condition usually cause? __________ pressure or
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negative pressure on the service or supply side. - CORRECT ANSWER-Reduced
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What does a double check valve backflow assembly provide effective protection from?
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Both backpressure and backsiphonage of ____________. - CORRECT ANSWER-
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Pollution
Il`
What is equipment that utilizes water for cooling, lubrication, washing or as a solvent
Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il`
Il`
always susceptible to? - CORRECT ANSWER-Cross-Connection
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Il` Il` Il` Il` Il`
What is the difference between a reduced pressure principle backflow device and a
Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il`
Il`
Il` Il`
double check backflow device? The RP has a ______________. - CORRECT
Il` Il` Il` Il` Il` Il` Il` Il` Il` Il`
Il`
ANSWER-Relief Valve
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Il`
What is the maximum time period between having a backflow device tested by a
Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il`
Il`
Il` Il`
certified backflow tester? ______________ year. - CORRECT ANSWER-1
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What is the regulatory definition of a cross-connection in a water supply? A physical
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connection between a public water system and any source of water or other substance
Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il`
that may lead to contamination of the water provided by the _____________ through
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backflow. - CORRECT ANSWER-PWS
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What is the name of a type of valve that reduces the differential pressure across a closed
Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il`
disk making the main valve easier to open and close? - CORRECT ANSWERBypass
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Valve
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As soon as Cl2 gas enters the throat area, a victim will sense a sudden stricture in this area-
Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il`
Nature's way of signaling to prevent passage of the gas to the lungs. At this point, the victim
Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il`
must attempt to do two things: get out of the area of the leak, proceeding upwind, and to
Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il`
take only very short breaths through the mouth. Normal breathing will cause __________,
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which must be prevented if possible. - CORRECT ANSWERCoughing
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, Il`
Chlorine gas causes suffocation, constriction of the chest, tightness in the throat, and
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Il`
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edema of the ______________. - CORRECT ANSWER-Lungs
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_______________ available chlorine is very effective in killing bacteria. - CORRECT Il`
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ANSWER-Free
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How should an operator store an empty chlorine cylinder? ____________, tagged as
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Il`
empty. - CORRECT ANSWER-Upright
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If a chlorine leak occurs, where will chlorine gas accumulate? Near the ____________
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Il`
Il` Il` Il` Il` Il`
of the tank. - CORRECT ANSWER-Bottom
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Il` Il` Il` Il` Il`
What effect does chlorine gas have on the sense of smell? It produces olfactory
Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il`
Il`
_______________. - CORRECT ANSWER-Fatigue
Il`
Il` Il` Il`
What is the primary safety concern when using chlorine gas as opposed to calcium
Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il`
Il`
Il`
hypochlorite or sodium hypochlorite? The potential for a _____________ leak. - Il` Il` Il` Il` Il` Il` Il` Il` Il` Il`
Il`
CORRECT ANSWER-Gas
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Il`
What may occur due to chronic exposure to low concentrations of chlorine gas? Chronic
Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il`
Il`
exposure may cause corrosion of the _____________. - CORRECT ANSWER-Teeth
Il`
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What is the process called that changes water vapor to tiny droplets or ice crystals? -
Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il`
Il`
CORRECT ANSWER-Condensation
Il`
Il`
What is the unit of measurement for sound? - CORRECT ANSWER-Decibels
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What happens if grease comes in contact with the winding of a motor? - CORRECT
Il` Il` Il` Il` Il` Il` Il` Il` Il`
Il`
Il` Il` Il` Il` Il` Il`
ANSWER-The winding insulation my deteriorate.
Il`
Il` Il` Il` Il`
What is the most common type of valve used in isolating a small or medium sized
Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il`
Il`
Il` Il` Il`
section of a distribution system? - CORRECT ANSWER-Gate
Il`
Il` Il` Il` Il` Il` Il` Il`
What is a possible result of over greasing a bearing? There is extreme _____________ in
Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il`
the bearing chamber causing heat and scoring of the shaft. - CORRECT ANSWERFriction
Il`
Il`
Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il`
What is meant by the term "peak demand?" The _____________ momentary load placed
Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il`
on a water treatment plant, pumping station or distribution system. - CORRECT
Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il`
ANSWER-Maximum
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Il`
What is the range of the pH scale? between _____________-14. - CORRECT
Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il`
Il`
ANSWER-Zero
Il`
What does a Bellows-type sensor reacts to a change in? _________________. -
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Il`
Il` Il` Il` Il` Il` Il` Il`
CORRECT ANSWER-Pressure
Il`
Il`
Centrifugal pumps do not generate suction unless the impeller is submerged in water. If Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il`
a pump is located above the level of water what must be provided on the suction piping
Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il`
Il`
Il` Il` Il` Il` Il`
to hold the prime? - CORRECT ANSWER-Foot Valve
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Il` Il` Il` Il` Il` Il` Il`
What causes pump cavitation? A suction line may be ____________ or the pump is above
Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il`
the waterline. You have overpumped the well. - CORRECT ANSWER-Clogged
Il`
Il`
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Il`
What does continuous leakage from a mechanical seal on a pump indicate? The
Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il` Il`
mechanical seal needs to be ___________________. - CORRECT ANSWER-Replaced
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