D2 - WATER DISTRIBUTION OPERATOR EXAM
(CALIFORNIA) QUESTIONS WITH CORRECT
ANSWERS 2026
Three sources of supply - - CORRECT ANSWERSurface water treatment plants, Import/Purchased water, and
Wells.
Transmission Main - - CORRECT ANSWERARvery large main designed to move water from one part of the
system to another.
Shut-Off Valve - - CORRECT ANSWERA 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
ANSWERUsually found connected to a consumer's meter.
Why might a water company need to shut water off to a particular consumer? - CORRECT
ANSWERBecause 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 ANSWERCurb stop & Angle stop.
Meters - CORRECT ANSWERDevices used to read consumer usage.
Where does a water company's property end - CORRECT ANSWERAt the consumer's meter.
Most common type of residential water meter and why? - - CORRECT ANSWERPositive displacement
meters, because they accurately measure all water that flows through them.
Three types of water systems - CORRECT ANSWERArterial loop, Grid, and Tree.
Minimum acceptable PSI with a system - CORRECT ANSWER20 PSI
, Normal acceptable range of PSI within a system - CORRECT ANSWER35 to 65 PSI
When must a pressure regulator be installed on a consumer's service line? - CORRECT
ANSWERGREATER than 80 PSI.
What is the highest acceptable PSI within a system, before a pressure regulator needs to be installed? -
CORRECT ANSWER80 PSI
Why are higher pressures generally not desired within a system? - CORRECT
ANSWERIt can damage plumbing fixtures.
Dynamic Pressure - CORRECT ANSWERThe pressure within a system when water is moving.
Six types of pipe found in a water distribution system - CORRECT
ANSWERDuctile Iron, Concrete, Steel, Asbestos Cement, Plastic and Gray
Cast Iron.
C-Value - CORRECT ANSWERThe measure of interior smoothness within a pipe.
What does a 140+ C-Value mean? - CORRECT
ANSWERVery smooth interior surface of a pipe (Plastic, AC,
Concrete)
What does a <100 C-Value mean? - - CORRECT ANSWERVery bad interior surface of a pipe (Tuburculated
old cast iron)
What is a Pnetrometer? - CORRECT ANSWERA tool for measuring the compressive strength of soil.
What is a Competent Person? - - CORRECT ANSWERAn 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 ANSWERWhen a trench is 5' or more in depth, or
hazardous soil conditions exist.
(CALIFORNIA) QUESTIONS WITH CORRECT
ANSWERS 2026
Three sources of supply - - CORRECT ANSWERSurface water treatment plants, Import/Purchased water, and
Wells.
Transmission Main - - CORRECT ANSWERARvery large main designed to move water from one part of the
system to another.
Shut-Off Valve - - CORRECT ANSWERA 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
ANSWERUsually found connected to a consumer's meter.
Why might a water company need to shut water off to a particular consumer? - CORRECT
ANSWERBecause 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 ANSWERCurb stop & Angle stop.
Meters - CORRECT ANSWERDevices used to read consumer usage.
Where does a water company's property end - CORRECT ANSWERAt the consumer's meter.
Most common type of residential water meter and why? - - CORRECT ANSWERPositive displacement
meters, because they accurately measure all water that flows through them.
Three types of water systems - CORRECT ANSWERArterial loop, Grid, and Tree.
Minimum acceptable PSI with a system - CORRECT ANSWER20 PSI
, Normal acceptable range of PSI within a system - CORRECT ANSWER35 to 65 PSI
When must a pressure regulator be installed on a consumer's service line? - CORRECT
ANSWERGREATER than 80 PSI.
What is the highest acceptable PSI within a system, before a pressure regulator needs to be installed? -
CORRECT ANSWER80 PSI
Why are higher pressures generally not desired within a system? - CORRECT
ANSWERIt can damage plumbing fixtures.
Dynamic Pressure - CORRECT ANSWERThe pressure within a system when water is moving.
Six types of pipe found in a water distribution system - CORRECT
ANSWERDuctile Iron, Concrete, Steel, Asbestos Cement, Plastic and Gray
Cast Iron.
C-Value - CORRECT ANSWERThe measure of interior smoothness within a pipe.
What does a 140+ C-Value mean? - CORRECT
ANSWERVery smooth interior surface of a pipe (Plastic, AC,
Concrete)
What does a <100 C-Value mean? - - CORRECT ANSWERVery bad interior surface of a pipe (Tuburculated
old cast iron)
What is a Pnetrometer? - CORRECT ANSWERA tool for measuring the compressive strength of soil.
What is a Competent Person? - - CORRECT ANSWERAn 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 ANSWERWhen a trench is 5' or more in depth, or
hazardous soil conditions exist.
