Class D Water License – Texas EXAM
QUESTIONS WITH CORRECT
SOLUTIONS||100% GUARANTEED
PASS||UPDATED 2026/2027
SYLLABUS||ALREADY GRADED
A+||<<NEWEST VERSION>>
It is possible to have positive bacteriological samples removed from your record.
(true/false) - ANSWER ✓ true
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
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
Calcium hypochlorite will cause explosions or fires if it contacts ________
material. - ANSWER ✓ organic
At room temperature, chlorine gas is greenish-yellow, has a pungent odor, is
________ times heavier than air. - ANSWER ✓ 2.5
The maximum sustained gas withdrawal rate from 150-lb. cylinders (vacuum
transmission) is ________ lb(s)./day per degree F. - ANSWER ✓ 1 lbs/day
Disinfection capacity for drinking water must be ________% greater than the
highest expected dosage. - ANSWER ✓ 50%
Small water systems often use ________ to disinfect their water supply. -
ANSWER ✓ hypochlorinators
Hypochlorinators consist of a mixing tank, water, ________ hypochlorite, or
________ hypochlorite and a chemical pump. - ANSWER ✓ sodium hypochlorite
calcium hypochlorite
Gas chlorinators use a rotameter to meter chlorine in ________ or grams/hr. -
ANSWER ✓ lbs/day
Dosage is the amount of chemical applied, demand is the amount of chemical used
up, ________ is the amount of chemical remaining after reacting with demand. -
ANSWER ✓ residual
, Minimum chlorine residuals of ________ (free) and ________ (combined) are
required in the far reaches of the distribution system. - ANSWER ✓ 0.2 (free)
0.5 (combined/total)
The DPD and chlorine reaction turns the water a ________ color. - ANSWER ✓
pink to red
Chlorine and water make two acids: hydrochloric (HCl) and ________ (HOCl).
a. hypochlorous
b. hypochloric
c. hyperclorous
d. hydrachloric - ANSWER ✓ a. hypochlorous
A Self-Contained Breathing Apparatus (________) must be readily available for
chlorine rooms. - ANSWER ✓ SCBA
Chlorinator rooms must have ________-level and ________-level screened vents.
a. window/ceiling
b. door/floor
c. high/floor
d. low/window - ANSWER ✓ c. high/floor
In chlorinator rooms, ________ must be provided to determine the amount of
disinfectant used and the amount remaining daily. - ANSWER ✓ scales
EPA requires any private, municipal, or industrial entity storing or using
________ pounds or more chlorine to have a chemical risk management program.
a. 2,000
b. 2,500
c. 3,000
d. 3,500 - ANSWER ✓ b. 2,500
Heat-sensitive pressure relief plugs in chlorine containers melt at about ________
degrees F. - ANSWER ✓ 160 degrees F
Hold an open bottle of ________% ammonium hydroxide under a suspected
chlorine leak. - ANSWER ✓ 10%
QUESTIONS WITH CORRECT
SOLUTIONS||100% GUARANTEED
PASS||UPDATED 2026/2027
SYLLABUS||ALREADY GRADED
A+||<<NEWEST VERSION>>
It is possible to have positive bacteriological samples removed from your record.
(true/false) - ANSWER ✓ true
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
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
Calcium hypochlorite will cause explosions or fires if it contacts ________
material. - ANSWER ✓ organic
At room temperature, chlorine gas is greenish-yellow, has a pungent odor, is
________ times heavier than air. - ANSWER ✓ 2.5
The maximum sustained gas withdrawal rate from 150-lb. cylinders (vacuum
transmission) is ________ lb(s)./day per degree F. - ANSWER ✓ 1 lbs/day
Disinfection capacity for drinking water must be ________% greater than the
highest expected dosage. - ANSWER ✓ 50%
Small water systems often use ________ to disinfect their water supply. -
ANSWER ✓ hypochlorinators
Hypochlorinators consist of a mixing tank, water, ________ hypochlorite, or
________ hypochlorite and a chemical pump. - ANSWER ✓ sodium hypochlorite
calcium hypochlorite
Gas chlorinators use a rotameter to meter chlorine in ________ or grams/hr. -
ANSWER ✓ lbs/day
Dosage is the amount of chemical applied, demand is the amount of chemical used
up, ________ is the amount of chemical remaining after reacting with demand. -
ANSWER ✓ residual
, Minimum chlorine residuals of ________ (free) and ________ (combined) are
required in the far reaches of the distribution system. - ANSWER ✓ 0.2 (free)
0.5 (combined/total)
The DPD and chlorine reaction turns the water a ________ color. - ANSWER ✓
pink to red
Chlorine and water make two acids: hydrochloric (HCl) and ________ (HOCl).
a. hypochlorous
b. hypochloric
c. hyperclorous
d. hydrachloric - ANSWER ✓ a. hypochlorous
A Self-Contained Breathing Apparatus (________) must be readily available for
chlorine rooms. - ANSWER ✓ SCBA
Chlorinator rooms must have ________-level and ________-level screened vents.
a. window/ceiling
b. door/floor
c. high/floor
d. low/window - ANSWER ✓ c. high/floor
In chlorinator rooms, ________ must be provided to determine the amount of
disinfectant used and the amount remaining daily. - ANSWER ✓ scales
EPA requires any private, municipal, or industrial entity storing or using
________ pounds or more chlorine to have a chemical risk management program.
a. 2,000
b. 2,500
c. 3,000
d. 3,500 - ANSWER ✓ b. 2,500
Heat-sensitive pressure relief plugs in chlorine containers melt at about ________
degrees F. - ANSWER ✓ 160 degrees F
Hold an open bottle of ________% ammonium hydroxide under a suspected
chlorine leak. - ANSWER ✓ 10%
