1
Class C Water Operator License Exam Questions with
Answers (100% Correct Answers)
Ammonia mixed with chlorine gas creates a Answer: white smoke
The most difficult part of a water distribution operator's job. Answer:
furnish a continuous supply
Physical connection between a safe and potentially unsafe water
source. Answer: cross connection
A distribution system is a Answer: looped system
Dead end mains should be flushed Answer: every month
Excess nitrate causes a condition called Answer: blue baby syndrome
Water hardness is caused by Answer: calcium and magnesium
Sewer mains should be __ft away from water mains. Answer: 9
Water with a pH less than 7 is considered to be Answer: acidic
Bacti records are kept for ____yrs and chemical records are kept for
___yrs. Answer: 5, 10
© 2025 All rights reserved
, 2
Bacti samples have to be returned to the lab within ___hrs of the
collection time. Answer: 30
Color in the water supply should be less than _____ units. Answer: 15
Chlorine is ______ times heavier than air. Answer: 2.5
90% of underground pipe failures are related to improper Answer:
backfill and bedding
The spoil bank should be located at least ___ft away from the ditch.
Answer: 2
The following minimum residuals is ______mg/L for free chlorine and
____mg/L for total chlorine. Answer: .2, .5
Public opinion of the water utility is _______ at a standstill. Answer:
never
A bacti sample should be taken every ____ft of pipe. Answer: 1000
The most common collection point for a bacti sample is the water tap
_______. Answer: outside the house
A standpipe is considered ground storage unless it exceeds _____ft
above the highest ________. Answer: 80, service connection
© 2025 All rights reserved
Class C Water Operator License Exam Questions with
Answers (100% Correct Answers)
Ammonia mixed with chlorine gas creates a Answer: white smoke
The most difficult part of a water distribution operator's job. Answer:
furnish a continuous supply
Physical connection between a safe and potentially unsafe water
source. Answer: cross connection
A distribution system is a Answer: looped system
Dead end mains should be flushed Answer: every month
Excess nitrate causes a condition called Answer: blue baby syndrome
Water hardness is caused by Answer: calcium and magnesium
Sewer mains should be __ft away from water mains. Answer: 9
Water with a pH less than 7 is considered to be Answer: acidic
Bacti records are kept for ____yrs and chemical records are kept for
___yrs. Answer: 5, 10
© 2025 All rights reserved
, 2
Bacti samples have to be returned to the lab within ___hrs of the
collection time. Answer: 30
Color in the water supply should be less than _____ units. Answer: 15
Chlorine is ______ times heavier than air. Answer: 2.5
90% of underground pipe failures are related to improper Answer:
backfill and bedding
The spoil bank should be located at least ___ft away from the ditch.
Answer: 2
The following minimum residuals is ______mg/L for free chlorine and
____mg/L for total chlorine. Answer: .2, .5
Public opinion of the water utility is _______ at a standstill. Answer:
never
A bacti sample should be taken every ____ft of pipe. Answer: 1000
The most common collection point for a bacti sample is the water tap
_______. Answer: outside the house
A standpipe is considered ground storage unless it exceeds _____ft
above the highest ________. Answer: 80, service connection
© 2025 All rights reserved
