Page 1 of 39
TEXAS CLASS D WATER OPERATOR LICENSE
(TCEQ) 2026 EXAM COMPLETE CURRENT
TESTING QUESTIONS AND DETAILED
CORRECT ANSWERS (VERIFIED)
GUARANTEED PASS/TOP-RATED A+.
WATER OPERATOR
Maximize your success on the Texas Class D Water Operator
License (TCEQ) exam with focused preparation that strengthens
your understanding of basic water treatment, disinfection, safe
distribution practices, and Texas Commission on Environmental
Quality regulations for small public water systems. It is
specifically designed for water operators in Texas seeking
certification to manage a Class D ground or surface water
facility.
A certain group of bacteria is used to indicate the possible
presence of a pathogen--- the ________ group. ✓ ✓......
ANSWER ....... Coliform
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Disinfection is the destruction of disease-causing
microorganisms called ______. ✓ ✓...... ANSWER .......
Pathogens
At room temperature chlorine is a greenish-yellow gas that is
___ times heavier than air. ✓ ✓...... ANSWER ....... 2.5
The State requires ________ to be kept in stock for
disinfecting new water lines. ✓ ✓...... ANSWER .......
Calcium hypochlorite
T/F: Hypochlorinators consist of a mixing tank and chemical
solution feed pump. ✓ ✓...... ANSWER ....... True
A full-face self-contained breathing apparatus or supplied
air respirator must be readily accessible outside the fire
station when chlorine gas is used. ✓ ✓...... ANSWER .......
False (A full-face self-contained breathing apparatus (SCBA)
or supplied air respirator that meets OSHA standards shall
be readily accessible outside the *chlorinator room* when
chlorine gas is used.)
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T/F: All public water systems must have chlorination
facilities. ✓ ✓...... ANSWER ....... True
If chlorine enters the eyes, flush with running cool water for
at least ___ minutes and seek medical attention. ✓ ✓......
ANSWER ....... 15 minutes
Liquid bleach used in PWS must be ______ approved. ✓
✓...... ANSWER ....... NSF
T/F: Primary components of a gas feed chlorinator include
an injector, flowrate controller, rotameter, and mixing tank.
✓ ✓...... ANSWER ....... False (injector, vacuum regulator,
flowrate controller, rotameter- *not a mixing tank*)
The maximum sustained gas withdrawal rate for pressure
transmission 150 lb cylinders is ____ lbs/day ✓ ✓......
ANSWER ....... 40
T/F: Utility operators use chlorine in three commercial forms:
1) pure chlorine in the liquid or gas state
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2) bleach solutions
3) granular/tablet compounds ✓ ✓...... ANSWER .......
True
T/F: If chlorine contacts the skin, flush with an emergency
shower or garden hose for at least an hour. ✓ ✓......
ANSWER ....... False (15 minutes)
Hypochlorous acid is the disinfectant and the _____ residual.
✓ ✓...... ANSWER ....... Free
If a major chlorine leak occurs, call the supplier and ______.
✓ ✓...... ANSWER ....... TCEQ
The rotameter indicates the feed rate in _____ per day ✓
✓...... ANSWER ....... pounds
T/F: Chlorine reacts with hydrocarbons producing heat or fire
✓ ✓...... ANSWER ....... True
TEXAS CLASS D WATER OPERATOR LICENSE
(TCEQ) 2026 EXAM COMPLETE CURRENT
TESTING QUESTIONS AND DETAILED
CORRECT ANSWERS (VERIFIED)
GUARANTEED PASS/TOP-RATED A+.
WATER OPERATOR
Maximize your success on the Texas Class D Water Operator
License (TCEQ) exam with focused preparation that strengthens
your understanding of basic water treatment, disinfection, safe
distribution practices, and Texas Commission on Environmental
Quality regulations for small public water systems. It is
specifically designed for water operators in Texas seeking
certification to manage a Class D ground or surface water
facility.
A certain group of bacteria is used to indicate the possible
presence of a pathogen--- the ________ group. ✓ ✓......
ANSWER ....... Coliform
, Page 2 of 39
Disinfection is the destruction of disease-causing
microorganisms called ______. ✓ ✓...... ANSWER .......
Pathogens
At room temperature chlorine is a greenish-yellow gas that is
___ times heavier than air. ✓ ✓...... ANSWER ....... 2.5
The State requires ________ to be kept in stock for
disinfecting new water lines. ✓ ✓...... ANSWER .......
Calcium hypochlorite
T/F: Hypochlorinators consist of a mixing tank and chemical
solution feed pump. ✓ ✓...... ANSWER ....... True
A full-face self-contained breathing apparatus or supplied
air respirator must be readily accessible outside the fire
station when chlorine gas is used. ✓ ✓...... ANSWER .......
False (A full-face self-contained breathing apparatus (SCBA)
or supplied air respirator that meets OSHA standards shall
be readily accessible outside the *chlorinator room* when
chlorine gas is used.)
, Page 3 of 39
T/F: All public water systems must have chlorination
facilities. ✓ ✓...... ANSWER ....... True
If chlorine enters the eyes, flush with running cool water for
at least ___ minutes and seek medical attention. ✓ ✓......
ANSWER ....... 15 minutes
Liquid bleach used in PWS must be ______ approved. ✓
✓...... ANSWER ....... NSF
T/F: Primary components of a gas feed chlorinator include
an injector, flowrate controller, rotameter, and mixing tank.
✓ ✓...... ANSWER ....... False (injector, vacuum regulator,
flowrate controller, rotameter- *not a mixing tank*)
The maximum sustained gas withdrawal rate for pressure
transmission 150 lb cylinders is ____ lbs/day ✓ ✓......
ANSWER ....... 40
T/F: Utility operators use chlorine in three commercial forms:
1) pure chlorine in the liquid or gas state
, Page 4 of 39
2) bleach solutions
3) granular/tablet compounds ✓ ✓...... ANSWER .......
True
T/F: If chlorine contacts the skin, flush with an emergency
shower or garden hose for at least an hour. ✓ ✓......
ANSWER ....... False (15 minutes)
Hypochlorous acid is the disinfectant and the _____ residual.
✓ ✓...... ANSWER ....... Free
If a major chlorine leak occurs, call the supplier and ______.
✓ ✓...... ANSWER ....... TCEQ
The rotameter indicates the feed rate in _____ per day ✓
✓...... ANSWER ....... pounds
T/F: Chlorine reacts with hydrocarbons producing heat or fire
✓ ✓...... ANSWER ....... True
