ILLINOIS CLASS D WATER FINAL
EXAM 2025 ACTUAL EXAM
COMPLETE EXAM QUESTIONS WITH
DETAILED VERIFIED ANSWERS
/BRAND NEW!! /ALREADY GRADED A+
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
Air relief valves in the distribution system should be
located where? - ....ANSWER...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? -
....ANSWER...20 psi
What could occur if the minimum distribution system
pressure is not maintained? -
....ANSWER...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? - ....ANSWER...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? - ....ANSWER...Every
month
When taking a bacteria sample, the sample bottle should
be filled with water: - ....ANSWER...to the 100mL line
While taking a bacteria water sample, what should also
be done at the same time and location? -
....ANSWER...chlorine residual test
,What is a chlorine residual and what does it show? -
....ANSWER...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: - ....ANSWER...repeat samples should be
taken. human or animal feces are present.
Sodium thiosulfate is added to Bac-T sampling bottles in
order to: - ....ANSWER...neutralize any chlorine in the
sample
For bacteria contamination, if repeat samples are
required, they should be taken: - ....ANSWER...within
24 hours
Which backflow preventer is most likely to be installed
as part of a water service line for a single family home? -
....ANSWER...dual check
, If practical, water mains should be how far above sewer
lines? - ....ANSWER...18 inches
Which water meter is most likely to be used for a single
family home? - ....ANSWER...Displacement meter
Older water meters for a single family home are most
likely to? - ....ANSWER...under register
Water storage system that uses compressed air to
increase water pressure: -
....ANSWER...Hydropneumatic
During pump operation, should water lubricated pump
packing leak? - ....ANSWER...Yes, at a steady dripping
rate
A dry chemical that is 65% available chlorine is being
used to provide a 50 mg/l disinfection dosage to a
completely full 95,000 gallon water storage tank.
Approximately how many pounds of chemical are need?
- ....ANSWER...61 lbs dry chemical
use pounds formula
95,000= 0.095 MG
EXAM 2025 ACTUAL EXAM
COMPLETE EXAM QUESTIONS WITH
DETAILED VERIFIED ANSWERS
/BRAND NEW!! /ALREADY GRADED A+
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
Air relief valves in the distribution system should be
located where? - ....ANSWER...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? -
....ANSWER...20 psi
What could occur if the minimum distribution system
pressure is not maintained? -
....ANSWER...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? - ....ANSWER...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? - ....ANSWER...Every
month
When taking a bacteria sample, the sample bottle should
be filled with water: - ....ANSWER...to the 100mL line
While taking a bacteria water sample, what should also
be done at the same time and location? -
....ANSWER...chlorine residual test
,What is a chlorine residual and what does it show? -
....ANSWER...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: - ....ANSWER...repeat samples should be
taken. human or animal feces are present.
Sodium thiosulfate is added to Bac-T sampling bottles in
order to: - ....ANSWER...neutralize any chlorine in the
sample
For bacteria contamination, if repeat samples are
required, they should be taken: - ....ANSWER...within
24 hours
Which backflow preventer is most likely to be installed
as part of a water service line for a single family home? -
....ANSWER...dual check
, If practical, water mains should be how far above sewer
lines? - ....ANSWER...18 inches
Which water meter is most likely to be used for a single
family home? - ....ANSWER...Displacement meter
Older water meters for a single family home are most
likely to? - ....ANSWER...under register
Water storage system that uses compressed air to
increase water pressure: -
....ANSWER...Hydropneumatic
During pump operation, should water lubricated pump
packing leak? - ....ANSWER...Yes, at a steady dripping
rate
A dry chemical that is 65% available chlorine is being
used to provide a 50 mg/l disinfection dosage to a
completely full 95,000 gallon water storage tank.
Approximately how many pounds of chemical are need?
- ....ANSWER...61 lbs dry chemical
use pounds formula
95,000= 0.095 MG
