D2 - WATER DISTRIBUTION OPERATOR EXAM (CALIFORNIA) QUESTIONS WITH CORRECT ANSWERS 2025

D2-WATERDISTRIBUTIONOPERATOREXAM f f f f f




(CALIFORNIA) QUESTIONS WITH CORRECT
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ANSWERS 2025 f f




Three sources of supply -RCORRECT ANSWER -
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Surface watertreatmentplants, Import/Purchasedwater, and Wells.
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Transmission Main- CORRECT ANSWER - f f f f f




ARvery large main designed to move water from one part of the system to another.
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Shut-Off Valve - CORRECT ANSWER - f f f f f




A type of valve the water company uses when they need to turn water off to a particular consumer.
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Where is a Shut-Off Valve typically located? - CORRECT ANSWER - Usually
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found connected to a consumer's meter.
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Why might a water company need to shut water off to a particular consumer? - CORRECT ANSWER - Because
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of a request to connect or disconnect, for repairs, or as a result of non payment.
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Two most common types of Shut-Off Valves - CORRECT ANSWER -Curb stop & Angle stop.
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Meters - CORRECT ANSWER -Devices used to read consumer usage.
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Where does a water company's property end - CORRECT ANSWER -At the consumer's meter.
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Most common type of residential water meter and why? - CORRECT ANSWER -
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Positive displacement meters, because they accurately measure allwater that flows through them.
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Three types of water systems - CORRECT ANSWER -Arterial loop, Grid, and Tree.
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Minimum acceptable PSI with a system - CORRECT ANSWER -20 PSI f f f f f f f f f f

, Normal acceptable range of PSI within a system - CORRECT ANSWER -35 to 65 PSI
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When must a pressure regulator be installed on a consumer's service line? - CORRECT ANSWER - GREATER
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than 80 PSI.
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What is the highest acceptable PSI within a system, before a pressure regulator needs to be installed? - CORRECT
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ANSWER -80 PSI
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Why are higher pressures generally not desired within a system? - CORRECT ANSWER - It can
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damage plumbing fixtures.
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Dynamic Pressure - CORRECT ANSWER -The pressure within a system when water is moving.
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Six types of pipe found in a water distribution system - CORRECT ANSWER - Ductile
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Iron, Concrete, Steel, Asbestos Cement, Plastic and Gray Cast Iron.
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C-Value - CORRECT ANSWER -The measure of interior smoothness within a pipe.
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What does a 140+ C-Value mean? - CORRECT ANSWER - Very
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smooth interior surface of a pipe (Plastic, AC, Concrete)
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What does a <100 C-Value mean? - CORRECT ANSWER -
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Very bad interior surface of a pipe (Tuburculated old cast iron)
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What is a Pnetrometer? - CORRECT ANSWER -A tool for measuring the compressive strength of soil.
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What is a Competent Person? - CORRECT ANSWER -
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An individual with excavation knowledge and training who is in charge of an excavation job, and who ha s the
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power to start work in the event of a hazard
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When is shoring generally required? - CORRECT ANSWER -
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When a trench is 5' or more in depth, or hazardous soil conditions exist.
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