ILLINOIS CLASS D WATER LICENSE
TEST 2025 EXAM ACTUAL WITH
COMPLETE QUESTIONS AND ANSWERS
Two Towers are both 125 feet high, when full, contain 122 feet of water. Tower 1 holds
150,000 gallons. Tower 2 holds 500,000 gallons. Each has a pressure gauge at the
base. Which will register the most pressure in psi? -correct answerBoth will be equal
If the water level in tower 1 is 118 feet what will the pressure reading be at the base -
correct answer51.1 psi
What is the definition of potable water -correct answerWater that does not contain
objectable pollution, contamination, or infective agents and is considered safe for
drinking
What is the first item used when installing a service line to a customer? -correct
answerCorporation stop
, If a meter to a residence is located in the basement what should be located between the
water main and the house -correct answercurb stop
A 5/8" x 3/4" water meter serves a residence. Over a period of years the meter
__________ in recording actual water used -correct answerDecreases
To isolate part of a distribution system what type of valve is commonly used? -correct
answerGate valve
Trihalomethanes (THMs) are caused by? -correct answerReaction of chlorinated water
with numeric materials found in surface water sources
The longer the contact time water and chlorine residuals enjoy the ________ the THM
level will probably be -correct answerHigher
THM's should be eliminated from finished water because they cause ? -correct
answerCancer
The maximum contaminant level for THM's is? -correct answer.080 mg/l
When collecting THM samples one sample must be taken at a site where the water has
been in the distribution system the longest time -correct answerTrue
An applicant for a class d test who has graduated high school but has no approved
training credits must have ____________ "hands on" experience -correct answer6
months
What type of water main is most likely to become contaminated from gasoline saturated
soil -correct answerPVC
What type of materials must not be used as backfill for water mains? -correct
answerCinders
Nitrate in levels above _________ mg/L can cause "blue baby" disease -correct
answer10
A boil order must be issued if systems pressure drops below 20 psi or if contaminated of
any part of the system is suspected. Why? -correct answerIt is a regulation of the
IEPA, and to protect the health of water consumers
A boil order should be issued for? -correct answerUntil further notice
Upon the issuance of a boil order the IEPA regional office should be notified of the order
because ________________? -correct answerIt's a state regulation
TEST 2025 EXAM ACTUAL WITH
COMPLETE QUESTIONS AND ANSWERS
Two Towers are both 125 feet high, when full, contain 122 feet of water. Tower 1 holds
150,000 gallons. Tower 2 holds 500,000 gallons. Each has a pressure gauge at the
base. Which will register the most pressure in psi? -correct answerBoth will be equal
If the water level in tower 1 is 118 feet what will the pressure reading be at the base -
correct answer51.1 psi
What is the definition of potable water -correct answerWater that does not contain
objectable pollution, contamination, or infective agents and is considered safe for
drinking
What is the first item used when installing a service line to a customer? -correct
answerCorporation stop
, If a meter to a residence is located in the basement what should be located between the
water main and the house -correct answercurb stop
A 5/8" x 3/4" water meter serves a residence. Over a period of years the meter
__________ in recording actual water used -correct answerDecreases
To isolate part of a distribution system what type of valve is commonly used? -correct
answerGate valve
Trihalomethanes (THMs) are caused by? -correct answerReaction of chlorinated water
with numeric materials found in surface water sources
The longer the contact time water and chlorine residuals enjoy the ________ the THM
level will probably be -correct answerHigher
THM's should be eliminated from finished water because they cause ? -correct
answerCancer
The maximum contaminant level for THM's is? -correct answer.080 mg/l
When collecting THM samples one sample must be taken at a site where the water has
been in the distribution system the longest time -correct answerTrue
An applicant for a class d test who has graduated high school but has no approved
training credits must have ____________ "hands on" experience -correct answer6
months
What type of water main is most likely to become contaminated from gasoline saturated
soil -correct answerPVC
What type of materials must not be used as backfill for water mains? -correct
answerCinders
Nitrate in levels above _________ mg/L can cause "blue baby" disease -correct
answer10
A boil order must be issued if systems pressure drops below 20 psi or if contaminated of
any part of the system is suspected. Why? -correct answerIt is a regulation of the
IEPA, and to protect the health of water consumers
A boil order should be issued for? -correct answerUntil further notice
Upon the issuance of a boil order the IEPA regional office should be notified of the order
because ________________? -correct answerIt's a state regulation
