1
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
, 2
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)
, 3
The velocity of water is measure in: - ..(answers)..Feet per Second
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
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
, 2
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)
, 3
The velocity of water is measure in: - ..(answers)..Feet per Second
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
