ILLINOIS CLASS D WATER FINAL EXAM 2025 ACTUAL EXAM
COMPLETE EXAM QUESTIONS WITH DETAILED VERIFIED
ANSWERS /BRAND NEW!! /ALREADY GRADED A+
For a water storage tank, cathodic protection is only effective for the: - (ANSWERS)tank areas
#$%^&
covered by water
For a water storage system, the purpose of an altitude valve is to prevent: -
(ANSWERS)overflows
Before using a water storage tank that has been disinfected, water from the tank must not show
the presense of: - (ANSWERS)coliforms
High trihalomethane (THMs) levels may cause: - (ANSWERS)cancer
A finished water with a negative Langelier Index may be: - (ANSWERS)corrosive
Water with pH scale less than 7 is considered: - (ANSWERS)acidic
pH scale of 7 is considered - (ANSWERS)neutral
pH scale of 8-14 is considered? - (ANSWERS)basic
How many gallons of water are in 1 cubic ft? - (ANSWERS)7.48 gallons
How many gallons of water are in 15 cubic ft? - (ANSWERS)15 x 7.48 = 112.2 gallons
How many cubic ft of water is 20 gallons? - (ANSWERS)20/7.48 = 2.67 cubic ft
1 gallon of water equals how many lbs? - (ANSWERS)8.34 lbs
16 gallons of water is how many lbs? - (ANSWERS)16 x 8.34 = 133.44 lbs
A 180 ft water tower would show what psi on the gauge located at the base? - (ANSWERS)180/
2.31 = 77.92 psi
Pump cavitation is most likely to occur when: - (ANSWERS)the top of the water source level is
lower than the impeller
1 pound per square inch is equal to how many feet of elevated water? - (ANSWERS)2.31 feet
For most centrifugal pumps, if the total dyanmic head decreases, the pump will: -
(ANSWERS)pump water at a faster rate in gpm. (less head to push against)
The velocity of water is measure in: - (ANSWERS)Feet per Second
, ILLINOIS CLASS D WATER FINAL EXAM 2025 ACTUAL EXAM
COMPLETE EXAM QUESTIONS WITH DETAILED VERIFIED
ANSWERS /BRAND NEW!! /ALREADY GRADED A+
#$%^&
Distance (feet)/Time (sec)
When water lines in a distribution system are installed parallel to sewer lines, they should be
located how far apart from the sewer lines? - (ANSWERS)10 ft
Air relief valves in the distribution system should be located where? - (ANSWERS)at the high
point on a main
What is the minimum psi that needs to be continually maintained in all parts of a water
distribution system? - (ANSWERS)20 psi
What could occur if the minimum distribution system pressure is not maintained? -
(ANSWERS)backsiphonage
A ground storage tank is 50 feet in diameter and 30 feet high. If the tank is being filled at a 10
feet rise in level per hour, how many gallons per minute are flowing into the tank? -
(ANSWERS)2,447 gpm
(Ignore the heighth)
.785 X 50ft x 50ft x (10ft/1hr) = 19,625 cubic ft/1hr
1 cubic ft = 7.48 gallons
(19,625 cubic ft/1hr) x (7.48 gal/1 cubic ft) = 146,795 gal per HR
60 mins = 1 HR
146,795/60= 2,446.58 GPM
The IEPA requires that routine bacteria samples be taken and analyzed how often? -
(ANSWERS)Every month
When taking a bacteria sample, the sample bottle should be filled with water: - (ANSWERS)to
the 100mL line
While taking a bacteria water sample, what should also be done at the same time and location?
- (ANSWERS)chlorine residual test
What is a chlorine residual and what does it show? - (ANSWERS)The actual amount of chlorine
remaining in the water to act as a disinfectant. Indicates that a sufficient amount of chlorine
was added to the water to inactivate bacteria and some viruses.
If coliform bacteria are found in a water sample. This indicates that: - (ANSWERS)repeat
samples should be taken. human or animal feces are present.
COMPLETE EXAM QUESTIONS WITH DETAILED VERIFIED
ANSWERS /BRAND NEW!! /ALREADY GRADED A+
For a water storage tank, cathodic protection is only effective for the: - (ANSWERS)tank areas
#$%^&
covered by water
For a water storage system, the purpose of an altitude valve is to prevent: -
(ANSWERS)overflows
Before using a water storage tank that has been disinfected, water from the tank must not show
the presense of: - (ANSWERS)coliforms
High trihalomethane (THMs) levels may cause: - (ANSWERS)cancer
A finished water with a negative Langelier Index may be: - (ANSWERS)corrosive
Water with pH scale less than 7 is considered: - (ANSWERS)acidic
pH scale of 7 is considered - (ANSWERS)neutral
pH scale of 8-14 is considered? - (ANSWERS)basic
How many gallons of water are in 1 cubic ft? - (ANSWERS)7.48 gallons
How many gallons of water are in 15 cubic ft? - (ANSWERS)15 x 7.48 = 112.2 gallons
How many cubic ft of water is 20 gallons? - (ANSWERS)20/7.48 = 2.67 cubic ft
1 gallon of water equals how many lbs? - (ANSWERS)8.34 lbs
16 gallons of water is how many lbs? - (ANSWERS)16 x 8.34 = 133.44 lbs
A 180 ft water tower would show what psi on the gauge located at the base? - (ANSWERS)180/
2.31 = 77.92 psi
Pump cavitation is most likely to occur when: - (ANSWERS)the top of the water source level is
lower than the impeller
1 pound per square inch is equal to how many feet of elevated water? - (ANSWERS)2.31 feet
For most centrifugal pumps, if the total dyanmic head decreases, the pump will: -
(ANSWERS)pump water at a faster rate in gpm. (less head to push against)
The velocity of water is measure in: - (ANSWERS)Feet per Second
, ILLINOIS CLASS D WATER FINAL EXAM 2025 ACTUAL EXAM
COMPLETE EXAM QUESTIONS WITH DETAILED VERIFIED
ANSWERS /BRAND NEW!! /ALREADY GRADED A+
#$%^&
Distance (feet)/Time (sec)
When water lines in a distribution system are installed parallel to sewer lines, they should be
located how far apart from the sewer lines? - (ANSWERS)10 ft
Air relief valves in the distribution system should be located where? - (ANSWERS)at the high
point on a main
What is the minimum psi that needs to be continually maintained in all parts of a water
distribution system? - (ANSWERS)20 psi
What could occur if the minimum distribution system pressure is not maintained? -
(ANSWERS)backsiphonage
A ground storage tank is 50 feet in diameter and 30 feet high. If the tank is being filled at a 10
feet rise in level per hour, how many gallons per minute are flowing into the tank? -
(ANSWERS)2,447 gpm
(Ignore the heighth)
.785 X 50ft x 50ft x (10ft/1hr) = 19,625 cubic ft/1hr
1 cubic ft = 7.48 gallons
(19,625 cubic ft/1hr) x (7.48 gal/1 cubic ft) = 146,795 gal per HR
60 mins = 1 HR
146,795/60= 2,446.58 GPM
The IEPA requires that routine bacteria samples be taken and analyzed how often? -
(ANSWERS)Every month
When taking a bacteria sample, the sample bottle should be filled with water: - (ANSWERS)to
the 100mL line
While taking a bacteria water sample, what should also be done at the same time and location?
- (ANSWERS)chlorine residual test
What is a chlorine residual and what does it show? - (ANSWERS)The actual amount of chlorine
remaining in the water to act as a disinfectant. Indicates that a sufficient amount of chlorine
was added to the water to inactivate bacteria and some viruses.
If coliform bacteria are found in a water sample. This indicates that: - (ANSWERS)repeat
samples should be taken. human or animal feces are present.
