ILLINOIS CLASS C WATER OPERATOR 220+ EXAM
QUESTIONS & CORRECT ANSWERS LATEST
2026/2027
What kind of Fluoride is used in a saturator - ANSWER-Sodium Fluoride
Mains should be separated how far from storm and sewer - ANSWER-10'
Horizontal 18" Verticle
Water main tuberculation is caused by? - ANSWER-Corrosive Water
What size service line and meter is in a residential home - ANSWER-1" Service
5/8 Meter
High Nitrate Levels cause - ANSWER-Blue Babies
High trihalomethane levels cause - ANSWER-Cancer
High sulfate levels cause - ANSWER-Diarrhea
A negative Langelier index may indicate - ANSWER-Corrosive water
A positive Langelier index can be produced by - ANSWER-Adding caustic soda
,During pumping operations a water lubricated mechanical seal should - ANSWER-
Not leak any water
During pumping operations a water lubricated pump packing should - ANSWER-
Leak water at a steady dripping rate
When taking a bacterial water sample the sample bottle should be filled -
ANSWER-1" from the top
Illinois EPA requires a routine bacteria sample be taken - ANSWER-Every month
Water supply should store - ANSWER-2x the average day
At sea level the maximum suction lift is - ANSWER-34 Feet
Pressure rating for plastic mains - ANSWER-160psi
Most common cause for low pressure is a - ANSWER-Dirty joint
When is shoring required in a ditch - ANSWER-5 Feet
When is a ladder required in a ditch - ANSWER-4 Feet
Required flow for ISO (Fire Fighting) - ANSWER-500 Gpm for 5-8 hours
Low Ph means - ANSWER-Hard, acidic
, What is the neutral Ph - ANSWER-7
4" Meters should be tested every - ANSWER-2-4 Years
Residential meters should be tested - ANSWER-5-10 years
Propeller meter is used for? - ANSWER-Treatment Plants
What is the best mechanical backflow preventer - ANSWER-RPZ
Mechanical back flow preventers must be tested - ANSWER-Every year
Backflow- - ANSWER-the reverse flow of contaminants through a cross-
connection into a drinkable water supply
Backsiphonage - ANSWER-Water is siphoned back into the distribution system
Air Gap - ANSWER-Best back flow preventer
What is the allowable percentage of water loss for lake water - ANSWER-8%
High Ph means - ANSWER-Soft, alkaline
How much of the ladder should protrude outside of the ditch - ANSWER-3 Feet
QUESTIONS & CORRECT ANSWERS LATEST
2026/2027
What kind of Fluoride is used in a saturator - ANSWER-Sodium Fluoride
Mains should be separated how far from storm and sewer - ANSWER-10'
Horizontal 18" Verticle
Water main tuberculation is caused by? - ANSWER-Corrosive Water
What size service line and meter is in a residential home - ANSWER-1" Service
5/8 Meter
High Nitrate Levels cause - ANSWER-Blue Babies
High trihalomethane levels cause - ANSWER-Cancer
High sulfate levels cause - ANSWER-Diarrhea
A negative Langelier index may indicate - ANSWER-Corrosive water
A positive Langelier index can be produced by - ANSWER-Adding caustic soda
,During pumping operations a water lubricated mechanical seal should - ANSWER-
Not leak any water
During pumping operations a water lubricated pump packing should - ANSWER-
Leak water at a steady dripping rate
When taking a bacterial water sample the sample bottle should be filled -
ANSWER-1" from the top
Illinois EPA requires a routine bacteria sample be taken - ANSWER-Every month
Water supply should store - ANSWER-2x the average day
At sea level the maximum suction lift is - ANSWER-34 Feet
Pressure rating for plastic mains - ANSWER-160psi
Most common cause for low pressure is a - ANSWER-Dirty joint
When is shoring required in a ditch - ANSWER-5 Feet
When is a ladder required in a ditch - ANSWER-4 Feet
Required flow for ISO (Fire Fighting) - ANSWER-500 Gpm for 5-8 hours
Low Ph means - ANSWER-Hard, acidic
, What is the neutral Ph - ANSWER-7
4" Meters should be tested every - ANSWER-2-4 Years
Residential meters should be tested - ANSWER-5-10 years
Propeller meter is used for? - ANSWER-Treatment Plants
What is the best mechanical backflow preventer - ANSWER-RPZ
Mechanical back flow preventers must be tested - ANSWER-Every year
Backflow- - ANSWER-the reverse flow of contaminants through a cross-
connection into a drinkable water supply
Backsiphonage - ANSWER-Water is siphoned back into the distribution system
Air Gap - ANSWER-Best back flow preventer
What is the allowable percentage of water loss for lake water - ANSWER-8%
High Ph means - ANSWER-Soft, alkaline
How much of the ladder should protrude outside of the ditch - ANSWER-3 Feet
