WATER DISTRIBUTION PRACTICE TEST D1
D2 EXAM SCRIPT STUDY GUIDE QUESTIONS
WITH ACCURATE ANSWERS
●● How long must water remain stagnant and undisturbed in the pipe
before a first draw down sample is collected for lead and copper
analysis?
Answer: At least 6 hours.
●● If at least 40 samples per month are collected from a public water
system, what is the minimum percentage of routine/repeat samples that
must test negative for total coliform?
Answer: 95%
●● If the water has low pH, what does that indicate?
Answer: Corrosive water
●● What is the purpose of a mechanical seal?
Answer: To prevent water leakage from the pump
●● What could cause a chlorine gas cylinder to frost?
Answer: Feed rate is too high
, ●● Which chemicals are formed when chlorine gas is injected into
water?
Answer: Hypochlorous acid and hydrochloric acid
●● Which of the following is true about the effectiveness of chlorine?
Answer: The lower pH, the better disinfection with chlorine
●● What does a high C factor for a pipe indicate?
Answer: Smooth pipe interior
●● What is a disadvantage of having a tree formation in the water
distribution system
Answer: Dead-end mains
●● If chlorine is injected into cold water, how would the cold
temperature affect the effectiveness of chlorine?
Answer: More contact time would be required
●● If a confined space has 20.9% oxygen content, what does this tell
you?
Answer: Confined space is safe to enter
D2 EXAM SCRIPT STUDY GUIDE QUESTIONS
WITH ACCURATE ANSWERS
●● How long must water remain stagnant and undisturbed in the pipe
before a first draw down sample is collected for lead and copper
analysis?
Answer: At least 6 hours.
●● If at least 40 samples per month are collected from a public water
system, what is the minimum percentage of routine/repeat samples that
must test negative for total coliform?
Answer: 95%
●● If the water has low pH, what does that indicate?
Answer: Corrosive water
●● What is the purpose of a mechanical seal?
Answer: To prevent water leakage from the pump
●● What could cause a chlorine gas cylinder to frost?
Answer: Feed rate is too high
, ●● Which chemicals are formed when chlorine gas is injected into
water?
Answer: Hypochlorous acid and hydrochloric acid
●● Which of the following is true about the effectiveness of chlorine?
Answer: The lower pH, the better disinfection with chlorine
●● What does a high C factor for a pipe indicate?
Answer: Smooth pipe interior
●● What is a disadvantage of having a tree formation in the water
distribution system
Answer: Dead-end mains
●● If chlorine is injected into cold water, how would the cold
temperature affect the effectiveness of chlorine?
Answer: More contact time would be required
●● If a confined space has 20.9% oxygen content, what does this tell
you?
Answer: Confined space is safe to enter
