Page |1
ILLINOIS CLASS D WATER FINAL EXAM 2025/2026 NEWEST
ACTUAL EXAM WITH COMPLETE QUESTIONS AND
VERIFIED ANSWERS |ALREADY GRADED A+|
A positive Langelier Index means the finished water is: -
ANSWERS-scale-forming
A negative Langelier Index means the finished water is: -
ANSWERS-corrosive
A Langelier Index of 0 (zero) means the finished water is: -
ANSWERS-stable
A water with a pH of 8 would be considered to be: -ANSWERS-
basic
A positive Langelier Index can be produced by adding: -
ANSWERS-caustic soda
(Sodium Hydroxide NaOH)
, Page |2
The action level for lead is: -ANSWERS-0.015 mg/l
Lead and Copper testing is done on samples from residential
kitchens or baths after: -ANSWERS-after the water has been
standing in the line for at least 6 hours
The action level for copper is: -ANSWERS-1300 ug/l (parts per
billion)
(or 1.3 mg/l)
A bacteria water sample must be mailed so that the labe analysis
can begin no later than: -ANSWERS-30 hours after the sample
was collected
To determine if water is safe to drink in regard to bacteria content,
a lab takes a minimum of: -ANSWERS-24 hours
If a water sample shows the presence of coliform bacteria, how
many repeat samples should be taken? -ANSWERS-3 repeat
samples
, Page |3
If a water sample shows the presence of coliform bacteria, what
follow up testing is done on the sample? -ANSWERS-E. Coli test
If the E. Coli test is positive, what has been indicated from the
sample? -ANSWERS-Recent contamination from human or
animal waste
A boil order should be issued whenever the following type of
water contamination is suspected: -ANSWERS-Bacteria
contamination
During a boil order, drinking or culinary water should be boiled for
at least: -ANSWERS-5 minutes
When collecting a total coliform sample, it is considered good
practice to: -ANSWERS-hold the cap with the threads facing
down
(less chance of airborne bacteria contamination)
ILLINOIS CLASS D WATER FINAL EXAM 2025/2026 NEWEST
ACTUAL EXAM WITH COMPLETE QUESTIONS AND
VERIFIED ANSWERS |ALREADY GRADED A+|
A positive Langelier Index means the finished water is: -
ANSWERS-scale-forming
A negative Langelier Index means the finished water is: -
ANSWERS-corrosive
A Langelier Index of 0 (zero) means the finished water is: -
ANSWERS-stable
A water with a pH of 8 would be considered to be: -ANSWERS-
basic
A positive Langelier Index can be produced by adding: -
ANSWERS-caustic soda
(Sodium Hydroxide NaOH)
, Page |2
The action level for lead is: -ANSWERS-0.015 mg/l
Lead and Copper testing is done on samples from residential
kitchens or baths after: -ANSWERS-after the water has been
standing in the line for at least 6 hours
The action level for copper is: -ANSWERS-1300 ug/l (parts per
billion)
(or 1.3 mg/l)
A bacteria water sample must be mailed so that the labe analysis
can begin no later than: -ANSWERS-30 hours after the sample
was collected
To determine if water is safe to drink in regard to bacteria content,
a lab takes a minimum of: -ANSWERS-24 hours
If a water sample shows the presence of coliform bacteria, how
many repeat samples should be taken? -ANSWERS-3 repeat
samples
, Page |3
If a water sample shows the presence of coliform bacteria, what
follow up testing is done on the sample? -ANSWERS-E. Coli test
If the E. Coli test is positive, what has been indicated from the
sample? -ANSWERS-Recent contamination from human or
animal waste
A boil order should be issued whenever the following type of
water contamination is suspected: -ANSWERS-Bacteria
contamination
During a boil order, drinking or culinary water should be boiled for
at least: -ANSWERS-5 minutes
When collecting a total coliform sample, it is considered good
practice to: -ANSWERS-hold the cap with the threads facing
down
(less chance of airborne bacteria contamination)
