D2 - WATER DISTRIBUTION OPERATOR EXAM
(CALIFORNIA) QUESTIONS WITH CORRECT
ANSWERS 2025
Three sources of supply -RCORRECT ANSWER -
Surface water treatment plants, Import/Purchased water, and Wells.
Transmission Main - CORRECT ANSWER -
ARvery large main designed to move water from one part of the system to another.
Shut-Off Valve - CORRECT ANSWER -
A type of valve the water company uses when they need to turn water off to a particular consumer.
Where is a Shut-Off Valve typically located? - CORRECT ANSWER -
Usually found connected to a consumer's meter.
Why might a water company need to shut water off to a particular consumer? - CORRECT ANSWER -
Because of a request to connect or disconnect, for repairs, or as a result of non payment.
Two most common types of Shut-Off Valves - CORRECT ANSWER -Curb stop & Angle stop.
Meters - CORRECT ANSWER -Devices used to read consumer usage.
Where does a water company's property end - CORRECT ANSWER -At the consumer's meter.
Most common type of residential water meter and why? - CORRECT ANSWER -
Positive displacement meters, because they accurately measure all water that flows through them.
Three types of water systems - CORRECT ANSWER -Arterial loop, Grid, and Tree.
Minimum acceptable PSI with a system - CORRECT ANSWER -20 PSI
, Normal acceptable range of PSI within a system - CORRECT ANSWER -35 to 65 PSI
When must a pressure regulator be installed on a consumer's service line? - CORRECT ANSWER -
GREATER than 80 PSI.
What is the highest acceptable PSI within a system, before a pressure regulator needs to be installed? -
CORRECT ANSWER -80 PSI
Why are higher pressures generally not desired within a system? - CORRECT ANSWER -
It can damage plumbing fixtures.
Dynamic Pressure - CORRECT ANSWER -The pressure within a system when water is moving.
Six types of pipe found in a water distribution system - CORRECT ANSWER -
Ductile Iron, Concrete, Steel, Asbestos Cement, Plastic and Gray Cast Iron.
C-Value - CORRECT ANSWER -The measure of interior smoothness within a pipe.
What does a 140+ C-Value mean? - CORRECT ANSWER -
Very smooth interior surface of a pipe (Plastic, AC, Concrete)
What does a <100 C-Value mean? - CORRECT ANSWER -
Very bad interior surface of a pipe (Tuburculated old cast iron)
What is a Pnetrometer? - CORRECT ANSWER -A tool for measuring the compressive strength of soil.
What is a Competent Person? - CORRECT ANSWER -
An individual with excavation knowledge and training who is in charge of an excavation job, and who ha
s the power to start work in the event of a hazard
When is shoring generally required? - CORRECT ANSWER -
When a trench is 5' or more in depth, or hazardous soil conditions exist.
(CALIFORNIA) QUESTIONS WITH CORRECT
ANSWERS 2025
Three sources of supply -RCORRECT ANSWER -
Surface water treatment plants, Import/Purchased water, and Wells.
Transmission Main - CORRECT ANSWER -
ARvery large main designed to move water from one part of the system to another.
Shut-Off Valve - CORRECT ANSWER -
A type of valve the water company uses when they need to turn water off to a particular consumer.
Where is a Shut-Off Valve typically located? - CORRECT ANSWER -
Usually found connected to a consumer's meter.
Why might a water company need to shut water off to a particular consumer? - CORRECT ANSWER -
Because of a request to connect or disconnect, for repairs, or as a result of non payment.
Two most common types of Shut-Off Valves - CORRECT ANSWER -Curb stop & Angle stop.
Meters - CORRECT ANSWER -Devices used to read consumer usage.
Where does a water company's property end - CORRECT ANSWER -At the consumer's meter.
Most common type of residential water meter and why? - CORRECT ANSWER -
Positive displacement meters, because they accurately measure all water that flows through them.
Three types of water systems - CORRECT ANSWER -Arterial loop, Grid, and Tree.
Minimum acceptable PSI with a system - CORRECT ANSWER -20 PSI
, Normal acceptable range of PSI within a system - CORRECT ANSWER -35 to 65 PSI
When must a pressure regulator be installed on a consumer's service line? - CORRECT ANSWER -
GREATER than 80 PSI.
What is the highest acceptable PSI within a system, before a pressure regulator needs to be installed? -
CORRECT ANSWER -80 PSI
Why are higher pressures generally not desired within a system? - CORRECT ANSWER -
It can damage plumbing fixtures.
Dynamic Pressure - CORRECT ANSWER -The pressure within a system when water is moving.
Six types of pipe found in a water distribution system - CORRECT ANSWER -
Ductile Iron, Concrete, Steel, Asbestos Cement, Plastic and Gray Cast Iron.
C-Value - CORRECT ANSWER -The measure of interior smoothness within a pipe.
What does a 140+ C-Value mean? - CORRECT ANSWER -
Very smooth interior surface of a pipe (Plastic, AC, Concrete)
What does a <100 C-Value mean? - CORRECT ANSWER -
Very bad interior surface of a pipe (Tuburculated old cast iron)
What is a Pnetrometer? - CORRECT ANSWER -A tool for measuring the compressive strength of soil.
What is a Competent Person? - CORRECT ANSWER -
An individual with excavation knowledge and training who is in charge of an excavation job, and who ha
s the power to start work in the event of a hazard
When is shoring generally required? - CORRECT ANSWER -
When a trench is 5' or more in depth, or hazardous soil conditions exist.
