Class C Water Operator License Exam 110 Questions and Correct Answers 2025.

Class C Water Operator License Exam 110
Questions and Correct Answers 2025
Ammonia mixed with chlorine gas creates a -

** white smoke



The most difficult part of a water distribution operator's job. -

** furnish a continuous supply



Physical connection between a safe and potentially unsafe water source. -

** cross connection



A distribution system is a -

** looped system



Dead end mains should be flushed -

** every month



Excess nitrate causes a condition called -

** blue baby syndrome



Water hardness is caused by -

** calcium and magnesium



Sewer mains should be __ft away from water mains. -

** 9



Water with a pH less than 7 is considered to be -

** acidic



Bacti records are kept for ____yrs and chemical records are kept for ___yrs. -

, ** 5, 10



Bacti samples have to be returned to the lab within ___hrs of the collection time. -

** 30



Color in the water supply should be less than _____ units. -

** 15



Chlorine is ______ times heavier than air. -

** 2.5



90% of underground pipe failures are related to improper -

** backfill and bedding



The spoil bank should be located at least ___ft away from the ditch. -

** 2



The following minimum residuals is ______mg/L for free chlorine and ____mg/L for total chlorine. -

** .2, .5



Public opinion of the water utility is _______ at a standstill. -

** never



A bacti sample should be taken every ____ft of pipe. -

** 1000



The most common collection point for a bacti sample is the water tap _______. -

** outside the house



A standpipe is considered ground storage unless it exceeds _____ft above the highest ________. -

** 80, service connection