D2 - Water Distribution
Operator (California) Exam
Study Guide – Practice
Questions with Verified
Answers. GRADED A+. Latest
2026/2027 Update
three sources of supply - Answer✔✔-Surface water treatment plants,
Import/Purchased water, and Wells.
Transmission Main - Answer✔✔-A very large main designed to move water
from one part of the system to another.
Shut-Off Valve - 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? - Answer✔✔-Usually found
connected to a consumer's meter.
,Why might a water company need to shut water off to a particular consumer? -
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 - Answer✔✔-Curb stop & Angle
stop.
Meters - Answer✔✔-Devices used to read consumer usage.
where does a water company's property end - Answer✔✔-At the consumer's
meter.
most common type of residential water meter and why? - Answer✔✔-Positive
displacement meters, because they accurately measure all water that flows
through them.
three types of water systems - Answer✔✔-Arterial loop, Grid, and Tree.
minimum acceptable PSI with a system - Answer✔✔-20 PSI
normal acceptable range of PSI within a system - Answer✔✔-35 to 65 PSI
When must a pressure regulator be installed on a consumer's service line? -
Answer✔✔-GREATER than 80 PSI.
What is the highest acceptable PSI within a system, before a pressure regulator
needs to be installed? - Answer✔✔-80 PSI
, Why are higher pressures generally not desired within a system? - Answer✔✔-
It can damage plumbing fixtures.
Dynamic Pressure - Answer✔✔-The pressure within a system when water is
moving.
six types of pipe found in a water distribution system - Answer✔✔-Ductile Iron,
Concrete, Steel, Asbestos Cement, Plastic and Gray Cast Iron.
C-Value - Answer✔✔-The measure of interior smoothness within a pipe.
What does a 140+ C-Value mean? - Answer✔✔-Very smooth interior surface of
a pipe (Plastic, AC, Concrete)
What does a <100 C-Value mean? - Answer✔✔-Very bad interior surface of a
pipe (Tuburculated old cast iron)
What is a Pnetrometer? - Answer✔✔-A tool for measuring the compressive
strength of soil.
What is a Competent Person? - Answer✔✔-An individual with excavation
knowledge and training who is in charge of an excavation job, and who has the
power to start work in the event of a hazard
When is shoring generally required? - Answer✔✔-When a trench is 5' or more
in depth, or hazardous soil conditions exist.
Operator (California) Exam
Study Guide – Practice
Questions with Verified
Answers. GRADED A+. Latest
2026/2027 Update
three sources of supply - Answer✔✔-Surface water treatment plants,
Import/Purchased water, and Wells.
Transmission Main - Answer✔✔-A very large main designed to move water
from one part of the system to another.
Shut-Off Valve - 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? - Answer✔✔-Usually found
connected to a consumer's meter.
,Why might a water company need to shut water off to a particular consumer? -
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 - Answer✔✔-Curb stop & Angle
stop.
Meters - Answer✔✔-Devices used to read consumer usage.
where does a water company's property end - Answer✔✔-At the consumer's
meter.
most common type of residential water meter and why? - Answer✔✔-Positive
displacement meters, because they accurately measure all water that flows
through them.
three types of water systems - Answer✔✔-Arterial loop, Grid, and Tree.
minimum acceptable PSI with a system - Answer✔✔-20 PSI
normal acceptable range of PSI within a system - Answer✔✔-35 to 65 PSI
When must a pressure regulator be installed on a consumer's service line? -
Answer✔✔-GREATER than 80 PSI.
What is the highest acceptable PSI within a system, before a pressure regulator
needs to be installed? - Answer✔✔-80 PSI
, Why are higher pressures generally not desired within a system? - Answer✔✔-
It can damage plumbing fixtures.
Dynamic Pressure - Answer✔✔-The pressure within a system when water is
moving.
six types of pipe found in a water distribution system - Answer✔✔-Ductile Iron,
Concrete, Steel, Asbestos Cement, Plastic and Gray Cast Iron.
C-Value - Answer✔✔-The measure of interior smoothness within a pipe.
What does a 140+ C-Value mean? - Answer✔✔-Very smooth interior surface of
a pipe (Plastic, AC, Concrete)
What does a <100 C-Value mean? - Answer✔✔-Very bad interior surface of a
pipe (Tuburculated old cast iron)
What is a Pnetrometer? - Answer✔✔-A tool for measuring the compressive
strength of soil.
What is a Competent Person? - Answer✔✔-An individual with excavation
knowledge and training who is in charge of an excavation job, and who has the
power to start work in the event of a hazard
When is shoring generally required? - Answer✔✔-When a trench is 5' or more
in depth, or hazardous soil conditions exist.
