1|Page
ILLINOIS CLASS D WATER LICENSE TEST 2025
NEWEST ACTUAL EXAM CURRENTLY TESTING
COMPLETE EXAM QUESTIONS WITH DETAILED
VERIFIED ANSWERS (100% CORRECT ANSWERS)
/ALREADY GRADED A+/ LATEST VERSION!!!!
For a water storage tank, cathodic protection is only
effective for the: - Answer-tank areas covered by water
For a water storage system, the purpose of an altitude
valve is to prevent: - Answer-overflows
Before using a water storage tank that has been
disinfected, water from the tank must not show the
presense of: - Answer-coliforms
High trihalomethane (THMs) levels may cause: - Answer-
cancer
A finished water with a negative Langelier Index may be: -
Answer-corrosive
,2|Page
Water with pH scale less than 7 is considered: - Answer-
acidic
pH scale of 7 is considered - Answer-neutral
pH scale of 8-14 is considered? - Answer-basic
How many gallons of water are in 1 cubic ft? - Answer-
7.48 gallons
How many gallons of water are in 15 cubic ft? - Answer-15
x 7.48 = 112.2 gallons
How many cubic ft of water is 20 gallons? - Answer-
20/7.48 = 2.67 cubic ft
1 gallon of water equals how many lbs? - Answer-8.34 lbs
16 gallons of water is how many lbs? - Answer-16 x 8.34 =
133.44 lbs
, 3|Page
A 180 ft water tower would show what psi on the gauge
located at the base? - Answer-180/ 2.31 = 77.92 psi
Pump cavitation is most likely to occur when: - Answer-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? - Answer-2.31 feet
For most centrifugal pumps, if the total dyanmic head
decreases, the pump will: - Answer-pump water at a faster
rate in gpm. (less head to push against)
The velocity of water is measure in: - Answer-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? - Answer-10 ft
ILLINOIS CLASS D WATER LICENSE TEST 2025
NEWEST ACTUAL EXAM CURRENTLY TESTING
COMPLETE EXAM QUESTIONS WITH DETAILED
VERIFIED ANSWERS (100% CORRECT ANSWERS)
/ALREADY GRADED A+/ LATEST VERSION!!!!
For a water storage tank, cathodic protection is only
effective for the: - Answer-tank areas covered by water
For a water storage system, the purpose of an altitude
valve is to prevent: - Answer-overflows
Before using a water storage tank that has been
disinfected, water from the tank must not show the
presense of: - Answer-coliforms
High trihalomethane (THMs) levels may cause: - Answer-
cancer
A finished water with a negative Langelier Index may be: -
Answer-corrosive
,2|Page
Water with pH scale less than 7 is considered: - Answer-
acidic
pH scale of 7 is considered - Answer-neutral
pH scale of 8-14 is considered? - Answer-basic
How many gallons of water are in 1 cubic ft? - Answer-
7.48 gallons
How many gallons of water are in 15 cubic ft? - Answer-15
x 7.48 = 112.2 gallons
How many cubic ft of water is 20 gallons? - Answer-
20/7.48 = 2.67 cubic ft
1 gallon of water equals how many lbs? - Answer-8.34 lbs
16 gallons of water is how many lbs? - Answer-16 x 8.34 =
133.44 lbs
, 3|Page
A 180 ft water tower would show what psi on the gauge
located at the base? - Answer-180/ 2.31 = 77.92 psi
Pump cavitation is most likely to occur when: - Answer-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? - Answer-2.31 feet
For most centrifugal pumps, if the total dyanmic head
decreases, the pump will: - Answer-pump water at a faster
rate in gpm. (less head to push against)
The velocity of water is measure in: - Answer-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? - Answer-10 ft
