Texas Class C Surface Water Exam Review
| 147 Questions and Verified Answers | 100%
Correct | Grade A (2026/2027)
This "Texas Class C Surface Water Exam Review: 147 questions & Answers" is a highly rated
set to use by operators preparing for the TCEQ Class C Water Operator license. It focuses on
Texas-specific surface water treatment processes, TCEQ rules, and essential math.
Mastering the Class C exam requires a solid understanding of specific operational principles,
regulations, and math formulas.
Key Concept Breakdown
The exam heavily tests practical operations that surface water operators face daily.
• Coagulation & Flocculation: Understanding chemicals like alum, ferric chloride, and
polymers used to destabilize particles. Flash mixing and gentle flocculation are crucial.
• Sedimentation & Filtration: Monitoring settleability, filter ripening, backwash rates,
and turbidity limits (usually mandated to stay below 0.3 NTU).
• Disinfection & CT Values: Understanding the "CT" concept (Concentration of
disinfectant \(\times \) Time of contact). The exam expects you to know how pH and
temperature affect chlorine effectiveness.
• TCEQ Rules: Knowledge of 30 Texas Administrative Code (TAC) Chapter 290. This
includes regulations for bacteriological sampling, reporting, and storage tank capacities.
• Math Formulas: Being able to calculate detention times, loading rates, filtration rates,
and chemical dosages.
Purchase and get full access to download this Essential Resource instantly
Q1. Which of the following will a sand filter NOT remove from water? [Multiple
Choice]
A) Dissolved oxygen
B) Suspended solids
1
, C) Turbidity
D) Colloidal particles
Answer: Dissolved oxygen
Explanation: A sand filter is designed to remove particulate matter, suspended solids, and reduce
turbidity by trapping particles in the filter media. Dissolved oxygen is a dissolved gas, not a
particulate contaminant, so it will pass through a sand filter and is not removed by filtration.
Distractors are wrong because sand filters do reduce suspended solids, lower turbidity, and
capture many colloidal particles (especially when properly coagulated and filtered).
Q2. Explain what the term "water stabilization" refers to in the text. [Short Answer]
Answer: Water stabilization refers to adjusting the water's pH (pH adjustment).
Explanation: In this context, ‘water stabilization’ is defined simply as pH adjustment. Changing
pH alters the water’s acidity or alkalinity to achieve the stable chemical condition the text treats
as stabilization.
Q3. Organics in surface water combine with halogen disinfectants to form
chloramines. [True/False]
A) True
B) False
Answer: False
Explanation: Organic matter in surface water reacts with halogen disinfectants (like chlorine) to
form trihalomethanes (THMs), a class of disinfection byproducts. Chloramines are formed when
chlorine is combined with ammonia, not directly from organics plus halogens.
Q4. Using the diagram, list the four traditional zones of a rectangular
sedimentation basin. [Short Answer]
Answer: Inlet zone, settling zone, outlet zone, and sludge zone.
Explanation: The four traditional zones partition a rectangular sedimentation basin into entry
(inlet), the area where particles settle (settling), the exit (outlet), and the area where settled
solids collect (sludge). Knowing these labels helps locate where settling and solids removal occur.
Q5. Organics present in surface water will combine with halogens to form which
class of disinfection by-products? [Multiple Choice]
A) Trihalomethanes
B) Haloacetic acids
2
, C) Chloramines
D) Nitrates
Answer: Trihalomethanes
Explanation: Organic matter in surface water can react with halogen disinfectants (such as
chlorine) to form disinfection by-products known as trihalomethanes (THMs). THMs are
regulated because they can have health consequences. Distractors are wrong because they refer
to other substances: 'Haloacetic acids' are another class of disinfection by-products but the text
specifically identifies THMs; 'Chloramines' are formed when ammonia is combined with chlorine
for disinfection, not from organics plus halogens; 'Nitrates' are inorganic nitrogen compounds
not produced by organics reacting with halogens.
Q6. The four traditional zones of a rectangular sedimentation basin are the inlet
zone, settling zone, outlet zone, and the sludge zone. [True/False]
A) True
B) False
Answer: True
Explanation: A rectangular sedimentation basin is traditionally divided into an inlet zone (where
flow enters and velocity is dissipated), a settling zone (where particles settle out under low
velocity), an outlet zone (where clarified water exits), and a sludge zone (where settled solids
accumulate). Designing and operating these zones properly improves particle removal during
sedimentation.
Q7. Explain what a non-permit confined space means according to OSHA
standards in the text. [Short Answer]
Answer: A non-permit confined space is a confined space that does not contain, and
does not have the potential to contain, any hazard capable of causing death.
Explanation: OSHA distinguishes confined spaces that pose a fatal-hazard risk from those that do
not. A non-permit confined space, as defined here, lacks hazards capable of causing death, so it
does not require the permit-entry controls associated with permit spaces.
Q8. Which of the following lists the four traditional zones of a rectangular
sedimentation basin? [Multiple Choice]
A) The inlet zone, settling zone, outlet zone, and the sludge zone
B) The inlet zone, rapid-mix zone, overflow zone, and wash zone
C) The clarifier zone, coagulation zone, outlet channel, and grit chamber
3
, D) The flocculation zone, filtration zone, settling basin, and discharge channel
Answer: The inlet zone, settling zone, outlet zone, and the sludge zone
Explanation: A rectangular straight-flow sedimentation basin is functionally divided into four
zones: an inlet zone where flow enters and initial settling begins; a settling zone where particles
slowly settle under low velocity; an outlet zone where clarified water is collected; and a sludge
zone where settled solids accumulate. This zoning promotes uniform flow and effective removal
of suspended solids. Distractors are wrong because they either omit one of the four functional
zones or substitute unrelated components (for example, pump or filter media are not part of the
basin’s traditional zones).
Q9. According to the TCEQ, a public water system is defined as any water system
that provides piped water for human consumption to at least how many service
connections year-round or regularly serves how many individuals daily for how
many days per year? [Multiple Choice]
A) (a) 15; (b) 25; (c) 60
B) (a) 10; (b) 20; (c) 30
C) (a) 25; (b) 50; (c) 90
D) (a) 50; (b) 250; (c) 365
Answer: (a) 15; (b) 25; (c) 60
Explanation: The TCEQ defines a public water system using three numeric thresholds: at least 15
service connections on a year-round basis, or regularly serving 25 individuals daily for at least 60
days per year. These thresholds determine when a system becomes regulated as a public water
system. Distractors are wrong because their numeric combinations do not match the statutory
thresholds and thus would misclassify systems (too high or too low to match the regulatory
definition).
Q10. When a coagulant reacts with finely divided and suspended material in raw
water, what is formed? [Multiple Choice]
A) Floc
B) Sludge
C) Colloid
D) Sediment
Answer: Floc
4
| 147 Questions and Verified Answers | 100%
Correct | Grade A (2026/2027)
This "Texas Class C Surface Water Exam Review: 147 questions & Answers" is a highly rated
set to use by operators preparing for the TCEQ Class C Water Operator license. It focuses on
Texas-specific surface water treatment processes, TCEQ rules, and essential math.
Mastering the Class C exam requires a solid understanding of specific operational principles,
regulations, and math formulas.
Key Concept Breakdown
The exam heavily tests practical operations that surface water operators face daily.
• Coagulation & Flocculation: Understanding chemicals like alum, ferric chloride, and
polymers used to destabilize particles. Flash mixing and gentle flocculation are crucial.
• Sedimentation & Filtration: Monitoring settleability, filter ripening, backwash rates,
and turbidity limits (usually mandated to stay below 0.3 NTU).
• Disinfection & CT Values: Understanding the "CT" concept (Concentration of
disinfectant \(\times \) Time of contact). The exam expects you to know how pH and
temperature affect chlorine effectiveness.
• TCEQ Rules: Knowledge of 30 Texas Administrative Code (TAC) Chapter 290. This
includes regulations for bacteriological sampling, reporting, and storage tank capacities.
• Math Formulas: Being able to calculate detention times, loading rates, filtration rates,
and chemical dosages.
Purchase and get full access to download this Essential Resource instantly
Q1. Which of the following will a sand filter NOT remove from water? [Multiple
Choice]
A) Dissolved oxygen
B) Suspended solids
1
, C) Turbidity
D) Colloidal particles
Answer: Dissolved oxygen
Explanation: A sand filter is designed to remove particulate matter, suspended solids, and reduce
turbidity by trapping particles in the filter media. Dissolved oxygen is a dissolved gas, not a
particulate contaminant, so it will pass through a sand filter and is not removed by filtration.
Distractors are wrong because sand filters do reduce suspended solids, lower turbidity, and
capture many colloidal particles (especially when properly coagulated and filtered).
Q2. Explain what the term "water stabilization" refers to in the text. [Short Answer]
Answer: Water stabilization refers to adjusting the water's pH (pH adjustment).
Explanation: In this context, ‘water stabilization’ is defined simply as pH adjustment. Changing
pH alters the water’s acidity or alkalinity to achieve the stable chemical condition the text treats
as stabilization.
Q3. Organics in surface water combine with halogen disinfectants to form
chloramines. [True/False]
A) True
B) False
Answer: False
Explanation: Organic matter in surface water reacts with halogen disinfectants (like chlorine) to
form trihalomethanes (THMs), a class of disinfection byproducts. Chloramines are formed when
chlorine is combined with ammonia, not directly from organics plus halogens.
Q4. Using the diagram, list the four traditional zones of a rectangular
sedimentation basin. [Short Answer]
Answer: Inlet zone, settling zone, outlet zone, and sludge zone.
Explanation: The four traditional zones partition a rectangular sedimentation basin into entry
(inlet), the area where particles settle (settling), the exit (outlet), and the area where settled
solids collect (sludge). Knowing these labels helps locate where settling and solids removal occur.
Q5. Organics present in surface water will combine with halogens to form which
class of disinfection by-products? [Multiple Choice]
A) Trihalomethanes
B) Haloacetic acids
2
, C) Chloramines
D) Nitrates
Answer: Trihalomethanes
Explanation: Organic matter in surface water can react with halogen disinfectants (such as
chlorine) to form disinfection by-products known as trihalomethanes (THMs). THMs are
regulated because they can have health consequences. Distractors are wrong because they refer
to other substances: 'Haloacetic acids' are another class of disinfection by-products but the text
specifically identifies THMs; 'Chloramines' are formed when ammonia is combined with chlorine
for disinfection, not from organics plus halogens; 'Nitrates' are inorganic nitrogen compounds
not produced by organics reacting with halogens.
Q6. The four traditional zones of a rectangular sedimentation basin are the inlet
zone, settling zone, outlet zone, and the sludge zone. [True/False]
A) True
B) False
Answer: True
Explanation: A rectangular sedimentation basin is traditionally divided into an inlet zone (where
flow enters and velocity is dissipated), a settling zone (where particles settle out under low
velocity), an outlet zone (where clarified water exits), and a sludge zone (where settled solids
accumulate). Designing and operating these zones properly improves particle removal during
sedimentation.
Q7. Explain what a non-permit confined space means according to OSHA
standards in the text. [Short Answer]
Answer: A non-permit confined space is a confined space that does not contain, and
does not have the potential to contain, any hazard capable of causing death.
Explanation: OSHA distinguishes confined spaces that pose a fatal-hazard risk from those that do
not. A non-permit confined space, as defined here, lacks hazards capable of causing death, so it
does not require the permit-entry controls associated with permit spaces.
Q8. Which of the following lists the four traditional zones of a rectangular
sedimentation basin? [Multiple Choice]
A) The inlet zone, settling zone, outlet zone, and the sludge zone
B) The inlet zone, rapid-mix zone, overflow zone, and wash zone
C) The clarifier zone, coagulation zone, outlet channel, and grit chamber
3
, D) The flocculation zone, filtration zone, settling basin, and discharge channel
Answer: The inlet zone, settling zone, outlet zone, and the sludge zone
Explanation: A rectangular straight-flow sedimentation basin is functionally divided into four
zones: an inlet zone where flow enters and initial settling begins; a settling zone where particles
slowly settle under low velocity; an outlet zone where clarified water is collected; and a sludge
zone where settled solids accumulate. This zoning promotes uniform flow and effective removal
of suspended solids. Distractors are wrong because they either omit one of the four functional
zones or substitute unrelated components (for example, pump or filter media are not part of the
basin’s traditional zones).
Q9. According to the TCEQ, a public water system is defined as any water system
that provides piped water for human consumption to at least how many service
connections year-round or regularly serves how many individuals daily for how
many days per year? [Multiple Choice]
A) (a) 15; (b) 25; (c) 60
B) (a) 10; (b) 20; (c) 30
C) (a) 25; (b) 50; (c) 90
D) (a) 50; (b) 250; (c) 365
Answer: (a) 15; (b) 25; (c) 60
Explanation: The TCEQ defines a public water system using three numeric thresholds: at least 15
service connections on a year-round basis, or regularly serving 25 individuals daily for at least 60
days per year. These thresholds determine when a system becomes regulated as a public water
system. Distractors are wrong because their numeric combinations do not match the statutory
thresholds and thus would misclassify systems (too high or too low to match the regulatory
definition).
Q10. When a coagulant reacts with finely divided and suspended material in raw
water, what is formed? [Multiple Choice]
A) Floc
B) Sludge
C) Colloid
D) Sediment
Answer: Floc
4
