Class C Water Operator License Exam with verified answers
2026/2027 version
Water hardness is caused by- correct answer>>>calcium and magnesium
Sewer mains should be __ft away from water mains.- correct answer>>>9
Water with a pH less than 7 is considered to be- correct answer>>>acidic
Bacti records are kept for ____yrs and chemical records are kept for ___yrs.- correct
answer>>>5, 10
Bacti samples have to be returned to the lab within ___hrs of the collection time.-
correct answer>>>30
Color in the water supply should be less than _____ units.- correct answer>>>15
Chlorine is ______ times heavier than air.- correct answer>>>2.5
90% of underground pipe failures are related to improper- correct answer>>>backfill
and bedding
The spoil bank should be located at least ___ft away from the ditch.- correct
answer>>>2
The following minimum residuals is ______mg/L for free chlorine and ____mg/L for total
chlorine.- correct answer>>>.2, .5
Public opinion of the water utility is _______ at a standstill.- correct answer>>>never
A bacti sample should be taken every ____ft of pipe.- correct answer>>>1000
The most common collection point for a bacti sample is the water tap _______.- correct
answer>>>outside the house
A standpipe is considered ground storage unless it exceeds _____ft above the highest
________.- correct answer>>>80, service connection
Ammonia mixed with chlorine gas creates a- correct answer>>>white smoke
The most difficult part of a water distribution operator's job.- correct answer>>>furnish a
continuous supply
Physical connection between a safe and potentially unsafe water source.- correct
answer>>>cross connection
, A distribution system is a- correct answer>>>looped system
Dead end mains should be flushed- correct answer>>>every month
Excess nitrate causes a condition called- correct answer>>>blue baby syndrome
________ protection is the electrochemical method for preventing ________ of metal
tanks.- correct answer>>>cathodic, corrosion
The _____ is the only cross connection control method approved by _______.- correct
answer>>>air gap, tceq
_______ on a pipeline depend on the _____ or coefficient of pipe roughness.- correct
answer>>>friction loss, c factor
__________ occurs whenever there is a ______ in the velocity or direction of water
flow.- correct answer>>>water hammer, sudden change
The ______ water pressure required by the rules and regulations is ____psi under any
and all conditions.- correct answer>>>minimum, 20
100, 150, 200 and 250 are approved classes of _____ _____.- correct
answer>>>working pressure
______ is used to anchor pipe bends.- correct answer>>>concrete
A general deposit of mineral particles evenly along the inside of the pipe is ________.-
correct answer>>>tuberculation
Shoring should be used if a ditch is ___ft or deeper.- correct answer>>>5
A written sample writing plan is required for _______ monitoring.- correct
answer>>>coliform
Ladders should be placed every ___ft in a ditch.- correct answer>>>25
An oxygen deficient atmosphere is defined as one which contains _____ than ______
% oxygen.- correct answer>>>less, 19.5
Characteristics of a Centrifugal Pump:
as the head _____ the discharge ________.- correct answer>>>increases, decreases
The operator should leave a ________ of slack in flexible tubing.- correct
answer>>>gooseneck
2026/2027 version
Water hardness is caused by- correct answer>>>calcium and magnesium
Sewer mains should be __ft away from water mains.- correct answer>>>9
Water with a pH less than 7 is considered to be- correct answer>>>acidic
Bacti records are kept for ____yrs and chemical records are kept for ___yrs.- correct
answer>>>5, 10
Bacti samples have to be returned to the lab within ___hrs of the collection time.-
correct answer>>>30
Color in the water supply should be less than _____ units.- correct answer>>>15
Chlorine is ______ times heavier than air.- correct answer>>>2.5
90% of underground pipe failures are related to improper- correct answer>>>backfill
and bedding
The spoil bank should be located at least ___ft away from the ditch.- correct
answer>>>2
The following minimum residuals is ______mg/L for free chlorine and ____mg/L for total
chlorine.- correct answer>>>.2, .5
Public opinion of the water utility is _______ at a standstill.- correct answer>>>never
A bacti sample should be taken every ____ft of pipe.- correct answer>>>1000
The most common collection point for a bacti sample is the water tap _______.- correct
answer>>>outside the house
A standpipe is considered ground storage unless it exceeds _____ft above the highest
________.- correct answer>>>80, service connection
Ammonia mixed with chlorine gas creates a- correct answer>>>white smoke
The most difficult part of a water distribution operator's job.- correct answer>>>furnish a
continuous supply
Physical connection between a safe and potentially unsafe water source.- correct
answer>>>cross connection
, A distribution system is a- correct answer>>>looped system
Dead end mains should be flushed- correct answer>>>every month
Excess nitrate causes a condition called- correct answer>>>blue baby syndrome
________ protection is the electrochemical method for preventing ________ of metal
tanks.- correct answer>>>cathodic, corrosion
The _____ is the only cross connection control method approved by _______.- correct
answer>>>air gap, tceq
_______ on a pipeline depend on the _____ or coefficient of pipe roughness.- correct
answer>>>friction loss, c factor
__________ occurs whenever there is a ______ in the velocity or direction of water
flow.- correct answer>>>water hammer, sudden change
The ______ water pressure required by the rules and regulations is ____psi under any
and all conditions.- correct answer>>>minimum, 20
100, 150, 200 and 250 are approved classes of _____ _____.- correct
answer>>>working pressure
______ is used to anchor pipe bends.- correct answer>>>concrete
A general deposit of mineral particles evenly along the inside of the pipe is ________.-
correct answer>>>tuberculation
Shoring should be used if a ditch is ___ft or deeper.- correct answer>>>5
A written sample writing plan is required for _______ monitoring.- correct
answer>>>coliform
Ladders should be placed every ___ft in a ditch.- correct answer>>>25
An oxygen deficient atmosphere is defined as one which contains _____ than ______
% oxygen.- correct answer>>>less, 19.5
Characteristics of a Centrifugal Pump:
as the head _____ the discharge ________.- correct answer>>>increases, decreases
The operator should leave a ________ of slack in flexible tubing.- correct
answer>>>gooseneck
