Class "C" Water Exam With 165 Latest
questions and answers Updated 2025/2026
Calcium Hypochlorite - Correct Answers A common chemical used in the disenfection of a small
II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II!
water supply is-
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II! A Cross Connection - Correct Answers A physical connection between a potable water supply
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II! and a house well would be-
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II! Demand - Correct Answers The amount of Chlorine in mg/L that is used by reacting with iron,
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II! organics, or bacteria is called? II! II! II! II!
II! Greenish Yellow color II! II!
Heavier than air II! II! II!
Pungent, Penetrating odor II! II!
Corrosive - Correct Answers All of the following are Physical characteristics of Chlorine gas-
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II! Solution feed pump - Correct Answers Which of the following would be considered a part of a
II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II!
II! hypo-chlorinator system? II!
II! Flow measuring device - Correct Answers According to state requirements, all public water
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II! supply wells should be provided with a raised concrete sealing block, screened vents and-
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II! The difference in static and pumping levels - Correct Answers The drawdown of a water well is
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II! determined by- II!
II! If it is more acidic or base - Correct Answers The pH of water indicates-
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,II! 0-14 - Correct Answers The pH of water is expressed by a scale of numbers ranging from-
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II! 7.0 - Correct Answers Water that is considered neutral is expressed on the pH scale at-
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II! Use of an approved, sterile container - Correct Answers Which of the following is a required
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II! step in collecting a routine distribution sample for bacteriological testing?
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II! Turbidity - Correct Answers Sand filtration will remove which of the following from surface
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II! water?
II! Taste and Odor control - Correct Answers Activated Carbon is used in a Surface Water Plant
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II! primarily for? II!
II! Alum and Ferric Chloride - Correct Answers Which of the following chemical(s) are commonly
II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II!
II! used as coagulants in surface water treatment?
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II! Screened Vents II!
An approved locking roof hatch
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An overflow pipe with hinged flap device
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Annual inspection and maintenance as needed - Correct Answers Ground storage tanks are
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required to be provided with which of the following?
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II! Painting II!
Cathodic protection II!
Water stabilization - Correct Answers An elevated storage tank should be protected against
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corrosion by-
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, II! 35 psi - Correct Answers A public water supply system should maintain residual pressure of 20
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II! psi and a minimum normal operating pressure of-
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II! 50 mg/L - Correct Answers Before a new or repaired water line is placed into service, it must be
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II! properly disinfected by providing a chlorine dosage of _____ and proper detention time.
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II! Aquifers - Correct Answers Water bearing formations beneath the earth's surface that are used
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II! as a source of water for public water supplies are-
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II! Determine water levels in the well - Correct Answers The purpose of an air line on a well is-II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II!
II! Reduce the amount of sand pumped - Correct Answers The mesh size is an important feature of
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II! a well screen because property sized openings should-
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II! pH, alkalinity, temperature, and chemical dosage - Correct Answers When treating surface
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II! water, the process of coagulation will be most affected by the-
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II! When the loss of head gauge indicated between 6 and 10 ft. - Correct Answers A rapid sand
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II! filter should be backwashed when- II! II! II! II!
II! 0.2 mg/L free chlorine residual
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0.5 mg/L chloramine residual for a surface water supply
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0.8 mg/L chloramine residual when using chloramine treatment
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0.5 mg/L free chlorine residual for a groundwater supply - Correct Answers Which of the
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following is an acceptable disinfection residual at the far reaches of the distribution system-
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II! 8.34 lbs - Correct Answers One gallon of water weighs-
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questions and answers Updated 2025/2026
Calcium Hypochlorite - Correct Answers A common chemical used in the disenfection of a small
II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II!
water supply is-
II! II! II!
II! A Cross Connection - Correct Answers A physical connection between a potable water supply
II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II!
II! and a house well would be-
II! II! II! II! II!
II! Demand - Correct Answers The amount of Chlorine in mg/L that is used by reacting with iron,
II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II!
II! organics, or bacteria is called? II! II! II! II!
II! Greenish Yellow color II! II!
Heavier than air II! II! II!
Pungent, Penetrating odor II! II!
Corrosive - Correct Answers All of the following are Physical characteristics of Chlorine gas-
II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II!
II! Solution feed pump - Correct Answers Which of the following would be considered a part of a
II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II!
II! hypo-chlorinator system? II!
II! Flow measuring device - Correct Answers According to state requirements, all public water
II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II!
II! supply wells should be provided with a raised concrete sealing block, screened vents and-
II! II! II! II! II! II! II! II! II! II! II! II! II!
II! The difference in static and pumping levels - Correct Answers The drawdown of a water well is
II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II!
II! determined by- II!
II! If it is more acidic or base - Correct Answers The pH of water indicates-
II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II!
,II! 0-14 - Correct Answers The pH of water is expressed by a scale of numbers ranging from-
II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II!
II! 7.0 - Correct Answers Water that is considered neutral is expressed on the pH scale at-
II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II!
II! Use of an approved, sterile container - Correct Answers Which of the following is a required
II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II!
II! step in collecting a routine distribution sample for bacteriological testing?
II! II! II! II! II! II! II! II! II!
II! Turbidity - Correct Answers Sand filtration will remove which of the following from surface
II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II!
II! water?
II! Taste and Odor control - Correct Answers Activated Carbon is used in a Surface Water Plant
II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II!
II! primarily for? II!
II! Alum and Ferric Chloride - Correct Answers Which of the following chemical(s) are commonly
II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II!
II! used as coagulants in surface water treatment?
II! II! II! II! II! II!
II! Screened Vents II!
An approved locking roof hatch
II! II! II! II!
An overflow pipe with hinged flap device
II! II! II! II! II! II!
Annual inspection and maintenance as needed - Correct Answers Ground storage tanks are
II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II!
required to be provided with which of the following?
II! II! II! II! II! II! II! II! II!
II! Painting II!
Cathodic protection II!
Water stabilization - Correct Answers An elevated storage tank should be protected against
II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II!
corrosion by-
II! II!
, II! 35 psi - Correct Answers A public water supply system should maintain residual pressure of 20
II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II!
II! psi and a minimum normal operating pressure of-
II! II! II! II! II! II! II!
II! 50 mg/L - Correct Answers Before a new or repaired water line is placed into service, it must be
II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II!
II! properly disinfected by providing a chlorine dosage of _____ and proper detention time.
II! II! II! II! II! II! II! II! II! II! II! II!
II! Aquifers - Correct Answers Water bearing formations beneath the earth's surface that are used
II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II!
II! as a source of water for public water supplies are-
II! II! II! II! II! II! II! II! II!
II! Determine water levels in the well - Correct Answers The purpose of an air line on a well is-II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II!
II! Reduce the amount of sand pumped - Correct Answers The mesh size is an important feature of
II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II!
II! a well screen because property sized openings should-
II! II! II! II! II! II! II!
II! pH, alkalinity, temperature, and chemical dosage - Correct Answers When treating surface
II! II! II! II! II! II! II! II! II! II! II! II! II! II! II!
II! water, the process of coagulation will be most affected by the-
II! II! II! II! II! II! II! II! II! II!
II! When the loss of head gauge indicated between 6 and 10 ft. - Correct Answers A rapid sand
II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II!
II! filter should be backwashed when- II! II! II! II!
II! 0.2 mg/L free chlorine residual
II! II! II! II!
0.5 mg/L chloramine residual for a surface water supply
II! II! II! II! II! II! II! II!
0.8 mg/L chloramine residual when using chloramine treatment
II! II! II! II! II! II! II!
0.5 mg/L free chlorine residual for a groundwater supply - Correct Answers Which of the
II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II!
following is an acceptable disinfection residual at the far reaches of the distribution system-
II! II! II! II! II! II! II! II! II! II! II! II! II! II!
II! 8.34 lbs - Correct Answers One gallon of water weighs-
II! II! II! II! II! II! II! II! II! II! II! II! II!
