AWWA PRACTICE TEST STUDY GUIDE
ACTUAL (UPDATED 2026) QUESTIONS
AND 100% CORRECT ANSWERS|| LATEST
UPDATE 2026
1.
What is the primary purpose of coagulation?
A. Kill bacteria
B. Remove dissolved solids
C. Destabilize particles
D. Add oxygen
Answer: C
Rationale: Coagulation neutralizes the electrical charges on suspended particles so they can
stick together. It does not remove dissolved solids or disinfect water.
2.
Which chemical is commonly used as a coagulant?
A. Chlorine
B. Alum
C. Fluoride
D. Lime
Answer: B
Rationale: Alum (aluminum sulfate) is widely used because it effectively destabilizes particles.
Chlorine disinfects, fluoride prevents tooth decay, and lime adjusts pH.
3.
Flocculation involves:
A. Rapid mixing
B. Gentle mixing
,C. Filtration
D. Disinfection
Answer: B
Rationale: After coagulation, gentle mixing allows particles to collide and form larger “flocs”
that can settle out.
4.
Sedimentation removes particles by:
A. Evaporation
B. Settling
C. Filtration
D. Oxidation
Answer: B
Rationale: Gravity causes heavier floc particles to settle to the bottom in sedimentation basins.
5.
Which filter type is most common?
A. Sand filter
B. Membrane filter
C. Carbon filter
D. Screen filter
Answer: A
Rationale: Rapid sand filters are widely used due to efficiency and cost-effectiveness.
6.
Turbidity measures:
A. Color
B. Clarity
C. Odor
D. Temperature
Answer: B
Rationale: Turbidity indicates how cloudy water is due to suspended particles.
,7.
Most common disinfectant:
A. Ozone
B. Chlorine
C. UV
D. Ammonia
Answer: B
Rationale: Chlorine is widely used because it is effective, economical, and provides residual
protection.
8.
CT in disinfection means:
A. Chemical time
B. Concentration × time
C. Chlorine treatment
D. Control temperature
Answer: B
Rationale: CT value determines how effective disinfection is based on disinfectant
concentration and contact time.
9.
Most chlorine-resistant pathogen:
A. Bacteria
B. Viruses
C. Giardia
D. Cryptosporidium
Answer: D
Rationale: Cryptosporidium has a strong outer shell, making it highly resistant to chlorine.
10.
, pH measures:
A. Oxygen level
B. Acidity/alkalinity
C. Turbidity
D. Hardness
Answer: B
Rationale: pH indicates how acidic or basic water is on a 0–14 scale.
11.
Best pH for alum coagulation:
A. 2–3
B. 4–5
C. 6–7
D. 9–10
Answer: C
Rationale: Alum works most effectively near neutral pH.
12.
Alkalinity is:
A. Oxygen content
B. Buffering capacity
C. Chlorine level
D. Turbidity
Answer: B
Rationale: Alkalinity helps resist pH changes, stabilizing water chemistry.
13.
Hardness is caused by:
A. Sodium
B. Calcium & magnesium
C. Iron
D. Chlorine
ACTUAL (UPDATED 2026) QUESTIONS
AND 100% CORRECT ANSWERS|| LATEST
UPDATE 2026
1.
What is the primary purpose of coagulation?
A. Kill bacteria
B. Remove dissolved solids
C. Destabilize particles
D. Add oxygen
Answer: C
Rationale: Coagulation neutralizes the electrical charges on suspended particles so they can
stick together. It does not remove dissolved solids or disinfect water.
2.
Which chemical is commonly used as a coagulant?
A. Chlorine
B. Alum
C. Fluoride
D. Lime
Answer: B
Rationale: Alum (aluminum sulfate) is widely used because it effectively destabilizes particles.
Chlorine disinfects, fluoride prevents tooth decay, and lime adjusts pH.
3.
Flocculation involves:
A. Rapid mixing
B. Gentle mixing
,C. Filtration
D. Disinfection
Answer: B
Rationale: After coagulation, gentle mixing allows particles to collide and form larger “flocs”
that can settle out.
4.
Sedimentation removes particles by:
A. Evaporation
B. Settling
C. Filtration
D. Oxidation
Answer: B
Rationale: Gravity causes heavier floc particles to settle to the bottom in sedimentation basins.
5.
Which filter type is most common?
A. Sand filter
B. Membrane filter
C. Carbon filter
D. Screen filter
Answer: A
Rationale: Rapid sand filters are widely used due to efficiency and cost-effectiveness.
6.
Turbidity measures:
A. Color
B. Clarity
C. Odor
D. Temperature
Answer: B
Rationale: Turbidity indicates how cloudy water is due to suspended particles.
,7.
Most common disinfectant:
A. Ozone
B. Chlorine
C. UV
D. Ammonia
Answer: B
Rationale: Chlorine is widely used because it is effective, economical, and provides residual
protection.
8.
CT in disinfection means:
A. Chemical time
B. Concentration × time
C. Chlorine treatment
D. Control temperature
Answer: B
Rationale: CT value determines how effective disinfection is based on disinfectant
concentration and contact time.
9.
Most chlorine-resistant pathogen:
A. Bacteria
B. Viruses
C. Giardia
D. Cryptosporidium
Answer: D
Rationale: Cryptosporidium has a strong outer shell, making it highly resistant to chlorine.
10.
, pH measures:
A. Oxygen level
B. Acidity/alkalinity
C. Turbidity
D. Hardness
Answer: B
Rationale: pH indicates how acidic or basic water is on a 0–14 scale.
11.
Best pH for alum coagulation:
A. 2–3
B. 4–5
C. 6–7
D. 9–10
Answer: C
Rationale: Alum works most effectively near neutral pH.
12.
Alkalinity is:
A. Oxygen content
B. Buffering capacity
C. Chlorine level
D. Turbidity
Answer: B
Rationale: Alkalinity helps resist pH changes, stabilizing water chemistry.
13.
Hardness is caused by:
A. Sodium
B. Calcium & magnesium
C. Iron
D. Chlorine
