CLASS D WATER LATEST
OPERATOR LICENSE
EXAM TCEQ QUESTIONS
AND ANSWERS 2026 - 2027
Which of the following is part of a hypochlorination system?
a) solution feed pump
b) gas cylinder
c) rotameter
d) injector/ejector
e) all of the above - ANSWERS-a) solution feed pump
An elevated storage tank should be protected against corrosion by:
a) painting
b) cathodic protection
c) water stabilization
d) all of the above
e) galvanizing - ANSWERS-d) all of the above (painting, cathodic
protection, and water stabilization)
The pH of water indicates whether it is acidic or basic and is expressed
by a scale of numbers ranging from:
END OF
PAGE
1
, CLASS D WATER LATEST
OPERATOR LICENSE
EXAM TCEQ QUESTIONS
AND ANSWERS 2026 - 2027
a) 0 - 7
b) 0 - 14
c) 1 - 7
d) 1 - 14
e) none of the above - ANSWERS-b) 0 - 14
Before a new main is placed into service, it must be properly disinfected
with a minimum chlorine dosage of:
a) 50 mg/L
b) 30 mg/L
c) 40 mg/L
d) 75 mg/L
e) 25 mg/L - ANSWERS-a) 50 mg/L
A common chemical used for disinfecting a small public water supply is:
a) soda ash
b) copper sulfate
END OF
PAGE
2
, CLASS D WATER LATEST
OPERATOR LICENSE
EXAM TCEQ QUESTIONS
AND ANSWERS 2026 - 2027
c) sodium hypochlorite
d) fluoride
e) sodium chloride - ANSWERS-c) sodium hypochlorite
Gravity filters will remove which of the following from surface water
supplies:
a) turbidity
b) taste and odors
c) nitrates
d) hardness
e) chlorides - ANSWERS-a) turbidity
If you added 3.5 mg/L of chlorine to your storage tank and 30 minutes
later measured the residual at 1.2 mg/L, what was the chlorine demand
in the tank?
a) 4.2
b) 2.9
END OF
PAGE
3
, CLASS D WATER LATEST
OPERATOR LICENSE
EXAM TCEQ QUESTIONS
AND ANSWERS 2026 - 2027
c) 0.3
d) 2.3
e) 4.7 - ANSWERS-d) 2.3
T/F: In Texas, about 75% of all water is used for commercial, industrial,
or agricultural purposes. - ANSWERS-True
Water covers approximately ________ of Earth's surface. - ANSWERS-
71%
Drought is an extended period when a region receives a deficiency in its
________ water supply. - ANSWERS-atmospheric, ground, or surface
T/F: Only about 1 gallon of tap water per person/day is used for drinking
and cooking - ANSWERS-True
END OF
PAGE
4
OPERATOR LICENSE
EXAM TCEQ QUESTIONS
AND ANSWERS 2026 - 2027
Which of the following is part of a hypochlorination system?
a) solution feed pump
b) gas cylinder
c) rotameter
d) injector/ejector
e) all of the above - ANSWERS-a) solution feed pump
An elevated storage tank should be protected against corrosion by:
a) painting
b) cathodic protection
c) water stabilization
d) all of the above
e) galvanizing - ANSWERS-d) all of the above (painting, cathodic
protection, and water stabilization)
The pH of water indicates whether it is acidic or basic and is expressed
by a scale of numbers ranging from:
END OF
PAGE
1
, CLASS D WATER LATEST
OPERATOR LICENSE
EXAM TCEQ QUESTIONS
AND ANSWERS 2026 - 2027
a) 0 - 7
b) 0 - 14
c) 1 - 7
d) 1 - 14
e) none of the above - ANSWERS-b) 0 - 14
Before a new main is placed into service, it must be properly disinfected
with a minimum chlorine dosage of:
a) 50 mg/L
b) 30 mg/L
c) 40 mg/L
d) 75 mg/L
e) 25 mg/L - ANSWERS-a) 50 mg/L
A common chemical used for disinfecting a small public water supply is:
a) soda ash
b) copper sulfate
END OF
PAGE
2
, CLASS D WATER LATEST
OPERATOR LICENSE
EXAM TCEQ QUESTIONS
AND ANSWERS 2026 - 2027
c) sodium hypochlorite
d) fluoride
e) sodium chloride - ANSWERS-c) sodium hypochlorite
Gravity filters will remove which of the following from surface water
supplies:
a) turbidity
b) taste and odors
c) nitrates
d) hardness
e) chlorides - ANSWERS-a) turbidity
If you added 3.5 mg/L of chlorine to your storage tank and 30 minutes
later measured the residual at 1.2 mg/L, what was the chlorine demand
in the tank?
a) 4.2
b) 2.9
END OF
PAGE
3
, CLASS D WATER LATEST
OPERATOR LICENSE
EXAM TCEQ QUESTIONS
AND ANSWERS 2026 - 2027
c) 0.3
d) 2.3
e) 4.7 - ANSWERS-d) 2.3
T/F: In Texas, about 75% of all water is used for commercial, industrial,
or agricultural purposes. - ANSWERS-True
Water covers approximately ________ of Earth's surface. - ANSWERS-
71%
Drought is an extended period when a region receives a deficiency in its
________ water supply. - ANSWERS-atmospheric, ground, or surface
T/F: Only about 1 gallon of tap water per person/day is used for drinking
and cooking - ANSWERS-True
END OF
PAGE
4
