Page 1 of 98
2026/2027 TCEQ CLASS D WATER LICENSE
EXAM BANK ALL COMPLETE CURRENT
TESTING QUESTIONS AND CORRECT
VERIFIED ANSWERS FOR GUARANTEED
PASS/TOP-RATED A+.
TCEQ
Maximize your success on the TCEQ Class D Water License exam
with focused preparation that strengthens your understanding of
surface water treatment processes, disinfection procedures,
and state regulations for operating a public water system in
Texas. It is specifically designed for water operators in Texas
seeking certification to manage and maintain Class D water
treatment facilities.
The purpose of the sample siting plan is to assure
bacteriological samples are taken from vacant houses.
(true/false) ...... ANSWER ....... false (vacant houses are
not ideal sampling sites as they may sit empty for long
amounts of time) ✓✓
, Page 2 of 98
_____ is put into bacteriological sample bottles to
dechlorinate the water. ...... ANSWER ....... Sodium
thiosulfate✓✓
Before taking a bacteriological sample, you should _____.
...... ANSWER ....... flush the service line✓✓
The bacteriological sample bottle should be completely
filled with sample water. (true/false) ...... ANSWER .......
false (only fill 100 ml unless the lab tells you otherwise)
✓✓
The monthly bacteriological sample should be marked
"construction." (true/false) ...... ANSWER ....... false (it
should be marked routine) ✓✓
Get bacteriological samples to the lab within _____ hours or
they are rejected. ...... ANSWER ....... 30✓✓
It is possible to have positive bacteriological samples
removed from your record. (true/false) ...... ANSWER .......
true✓✓
, Page 3 of 98
It is _____ public health risk if a positive fecal coliform repeat
sample or a positive total coliform repeat sample follows a
positive fecal coliform routine sample. ...... ANSWER .......
an acute✓✓
Acute violations require public notification within 72 hours
by radio and television using the words "Minor Health
Concern." (true/false) ...... ANSWER ....... false (it's a
major health concern) ✓✓
In the event of low distribution pressure (below _____ psi),
water outages, repeated unacceptable microbiological
samples, or failure to maintain adequate chlorine residuals,
special precautions must be instituted by the water system.
...... ANSWER ....... 20 psi✓✓
In Texas, all public water systems are required to have
________ facilities.
a. ozonation
b. chlorination
c. softening
, Page 4 of 98
d. trihalomethane ...... ANSWER ....... b.
chlorination✓✓
Chlorination is the most important process in the production
of ________ water. ...... ANSWER ....... potable✓✓
Besides disinfection, chlorine is used for taste and odor
control and ________.
a. oxidation of iron and manganese
b. oxidation of hydrogen sulfide
c. disinfection of repairs
d. all listed ...... ANSWER ....... d. all listed✓✓
Sodium hypochlorite is liquid ________. ...... ANSWER .......
bleach✓✓
Bleach used in public water systems must be ________
approved. ...... ANSWER ....... NSF✓✓
Calcium hypochlorite is made by reacting chlorine with
________. ...... ANSWER ....... lime✓✓
2026/2027 TCEQ CLASS D WATER LICENSE
EXAM BANK ALL COMPLETE CURRENT
TESTING QUESTIONS AND CORRECT
VERIFIED ANSWERS FOR GUARANTEED
PASS/TOP-RATED A+.
TCEQ
Maximize your success on the TCEQ Class D Water License exam
with focused preparation that strengthens your understanding of
surface water treatment processes, disinfection procedures,
and state regulations for operating a public water system in
Texas. It is specifically designed for water operators in Texas
seeking certification to manage and maintain Class D water
treatment facilities.
The purpose of the sample siting plan is to assure
bacteriological samples are taken from vacant houses.
(true/false) ...... ANSWER ....... false (vacant houses are
not ideal sampling sites as they may sit empty for long
amounts of time) ✓✓
, Page 2 of 98
_____ is put into bacteriological sample bottles to
dechlorinate the water. ...... ANSWER ....... Sodium
thiosulfate✓✓
Before taking a bacteriological sample, you should _____.
...... ANSWER ....... flush the service line✓✓
The bacteriological sample bottle should be completely
filled with sample water. (true/false) ...... ANSWER .......
false (only fill 100 ml unless the lab tells you otherwise)
✓✓
The monthly bacteriological sample should be marked
"construction." (true/false) ...... ANSWER ....... false (it
should be marked routine) ✓✓
Get bacteriological samples to the lab within _____ hours or
they are rejected. ...... ANSWER ....... 30✓✓
It is possible to have positive bacteriological samples
removed from your record. (true/false) ...... ANSWER .......
true✓✓
, Page 3 of 98
It is _____ public health risk if a positive fecal coliform repeat
sample or a positive total coliform repeat sample follows a
positive fecal coliform routine sample. ...... ANSWER .......
an acute✓✓
Acute violations require public notification within 72 hours
by radio and television using the words "Minor Health
Concern." (true/false) ...... ANSWER ....... false (it's a
major health concern) ✓✓
In the event of low distribution pressure (below _____ psi),
water outages, repeated unacceptable microbiological
samples, or failure to maintain adequate chlorine residuals,
special precautions must be instituted by the water system.
...... ANSWER ....... 20 psi✓✓
In Texas, all public water systems are required to have
________ facilities.
a. ozonation
b. chlorination
c. softening
, Page 4 of 98
d. trihalomethane ...... ANSWER ....... b.
chlorination✓✓
Chlorination is the most important process in the production
of ________ water. ...... ANSWER ....... potable✓✓
Besides disinfection, chlorine is used for taste and odor
control and ________.
a. oxidation of iron and manganese
b. oxidation of hydrogen sulfide
c. disinfection of repairs
d. all listed ...... ANSWER ....... d. all listed✓✓
Sodium hypochlorite is liquid ________. ...... ANSWER .......
bleach✓✓
Bleach used in public water systems must be ________
approved. ...... ANSWER ....... NSF✓✓
Calcium hypochlorite is made by reacting chlorine with
________. ...... ANSWER ....... lime✓✓
