AWTO: ARIZONA WATER TREATMENT OPERATOR CERTIFICATION GRADE 2 |
EXAM COMPLETE QUESTIONS AND 100% VERIFIED ANSWERS | LATEST
VERSION 2026/2027 (PASS GUARANTEE)
1. What is the minimum free chlorine residual required at the entry point to the
distribution system under Arizona Administrative Code?
A. 0.1 mg/L
B. 0.2 mg/L ANSWER
C. 0.5 mg/L
D. 1.0 mg/L
2. Under the Safe Drinking Water Act, which agency has primary enforcement
responsibility (primacy) for public water systems in Arizona?
A. U.S. Environmental Protection Agency
B. Arizona Department of Environmental Quality ANSWER
C. Arizona Department of Health Services
D. Arizona Water Quality Association
3. A community water system is defined as one that serves at least how many
people year-round?
A. 10 people or 5 service connections
B. 25 people or 15 service connections ANSWER
C. 50 people or 25 service connections
D. 100 people or 50 service connections
4. How long must a water system retain its operation records under Arizona
regulations?
A. 1 year
B. 3 years
C. 5 years
D. 10 years ANSWER
5. Which of the following is classified as a Tier 1 public notification violation
requiring notification within 24 hours?
A. Exceeding a secondary MCL
, B. A monitoring violation
C. Presence of E. coli in the distribution system ANSWER
D. Exceeding the nitrate MCL
6. Annual Consumer Confidence Reports must be delivered to customers by what
date?
A. January 1
B. April 1
C. July 1 ANSWER
D. October 1
7. Which type of public water system serves at least 25 people for at least 60 days
per year but is not a community water system?
A. Transient non-community water system
B. Non-transient non-community water system ANSWER
C. Seasonal water system
D. Private water system
8. The Maximum Contaminant Level Goal (MCLG) for lead in drinking water is:
A. 0.015 mg/L
B. 0.005 mg/L
C. 0.001 mg/L
D. Zero ANSWER
9. Under Arizona rules, a Grade 2 Water Treatment Operator must have how many
years of water treatment experience?
A. 1 year
B. 2 years ANSWER
C. 3 years
D. 4 years
10. What is the Maximum Contaminant Level (MCL) for total trihalomethanes
(TTHMs) in drinking water?
A. 0.010 mg/L
B. 0.040 mg/L
C. 0.080 mg/L ANSWER
D. 0.100 mg/L
,11. Which of the following sources is considered a groundwater source?
A. River
B. Reservoir
C. Artesian well ANSWER
D. Surface impoundment
12. Turbidity in source water is primarily caused by:
A. Dissolved salts
B. Suspended solids and colloidal particles ANSWER
C. Chlorine demand
D. Hardness
13. Stratification in a reservoir is caused mainly by:
A. Wind mixing
B. Temperature differences between layers ANSWER
C. Algae growth
D. Sedimentation
14. The process of drawing water from different depths in a reservoir to obtain the
best quality is called:
A. Selective withdrawal ANSWER
B. Blending
C. Destratification
D. Pre-sedimentation
15. Taste and odor problems in surface water supplies are commonly associated
with:
A. High turbidity
B. Low pH
C. Algae blooms ANSWER
D. High iron content
16. Which of the following best describes a confined aquifer?
A. An aquifer with a water table open to the atmosphere
B. An aquifer bounded above by an impermeable layer ANSWER
C. An aquifer recharged directly by rainfall
D. A shallow aquifer near the surface
17. Pre-sedimentation basins are primarily used to remove:
, A. Dissolved organics
B. Large suspended solids and grit ANSWER
C. Bacteria
D. Hardness
18. Algae in a source water reservoir can cause which treatment problem?
A. Reduced coagulation effectiveness
B. Increased pH
C. Taste, odor, and filter clogging ANSWER
D. Decreased turbidity
19. Which parameter is most indicative of microbial contamination potential in
source water?
A. Total dissolved solids
B. Fecal coliform or E. coli ANSWER
C. Iron concentration
D. Hardness
20. Groundwater under the direct influence of surface water (GUDISW) must be
treated as:
A. Groundwater only
B. Surface water ANSWER
C. Reclaimed water
D. Blended water
SECTION 3: COAGULATION AND FLOCCULATION
21. The purpose of coagulation in water treatment is to:
A. Remove dissolved gases
B. Destabilize colloidal particles so they can clump together ANSWER
C. Kill pathogens
D. Remove hardness
22. The most common coagulant used in water treatment is:
A. Lime
B. Soda ash
C. Alum (aluminum sulfate) ANSWER
EXAM COMPLETE QUESTIONS AND 100% VERIFIED ANSWERS | LATEST
VERSION 2026/2027 (PASS GUARANTEE)
1. What is the minimum free chlorine residual required at the entry point to the
distribution system under Arizona Administrative Code?
A. 0.1 mg/L
B. 0.2 mg/L ANSWER
C. 0.5 mg/L
D. 1.0 mg/L
2. Under the Safe Drinking Water Act, which agency has primary enforcement
responsibility (primacy) for public water systems in Arizona?
A. U.S. Environmental Protection Agency
B. Arizona Department of Environmental Quality ANSWER
C. Arizona Department of Health Services
D. Arizona Water Quality Association
3. A community water system is defined as one that serves at least how many
people year-round?
A. 10 people or 5 service connections
B. 25 people or 15 service connections ANSWER
C. 50 people or 25 service connections
D. 100 people or 50 service connections
4. How long must a water system retain its operation records under Arizona
regulations?
A. 1 year
B. 3 years
C. 5 years
D. 10 years ANSWER
5. Which of the following is classified as a Tier 1 public notification violation
requiring notification within 24 hours?
A. Exceeding a secondary MCL
, B. A monitoring violation
C. Presence of E. coli in the distribution system ANSWER
D. Exceeding the nitrate MCL
6. Annual Consumer Confidence Reports must be delivered to customers by what
date?
A. January 1
B. April 1
C. July 1 ANSWER
D. October 1
7. Which type of public water system serves at least 25 people for at least 60 days
per year but is not a community water system?
A. Transient non-community water system
B. Non-transient non-community water system ANSWER
C. Seasonal water system
D. Private water system
8. The Maximum Contaminant Level Goal (MCLG) for lead in drinking water is:
A. 0.015 mg/L
B. 0.005 mg/L
C. 0.001 mg/L
D. Zero ANSWER
9. Under Arizona rules, a Grade 2 Water Treatment Operator must have how many
years of water treatment experience?
A. 1 year
B. 2 years ANSWER
C. 3 years
D. 4 years
10. What is the Maximum Contaminant Level (MCL) for total trihalomethanes
(TTHMs) in drinking water?
A. 0.010 mg/L
B. 0.040 mg/L
C. 0.080 mg/L ANSWER
D. 0.100 mg/L
,11. Which of the following sources is considered a groundwater source?
A. River
B. Reservoir
C. Artesian well ANSWER
D. Surface impoundment
12. Turbidity in source water is primarily caused by:
A. Dissolved salts
B. Suspended solids and colloidal particles ANSWER
C. Chlorine demand
D. Hardness
13. Stratification in a reservoir is caused mainly by:
A. Wind mixing
B. Temperature differences between layers ANSWER
C. Algae growth
D. Sedimentation
14. The process of drawing water from different depths in a reservoir to obtain the
best quality is called:
A. Selective withdrawal ANSWER
B. Blending
C. Destratification
D. Pre-sedimentation
15. Taste and odor problems in surface water supplies are commonly associated
with:
A. High turbidity
B. Low pH
C. Algae blooms ANSWER
D. High iron content
16. Which of the following best describes a confined aquifer?
A. An aquifer with a water table open to the atmosphere
B. An aquifer bounded above by an impermeable layer ANSWER
C. An aquifer recharged directly by rainfall
D. A shallow aquifer near the surface
17. Pre-sedimentation basins are primarily used to remove:
, A. Dissolved organics
B. Large suspended solids and grit ANSWER
C. Bacteria
D. Hardness
18. Algae in a source water reservoir can cause which treatment problem?
A. Reduced coagulation effectiveness
B. Increased pH
C. Taste, odor, and filter clogging ANSWER
D. Decreased turbidity
19. Which parameter is most indicative of microbial contamination potential in
source water?
A. Total dissolved solids
B. Fecal coliform or E. coli ANSWER
C. Iron concentration
D. Hardness
20. Groundwater under the direct influence of surface water (GUDISW) must be
treated as:
A. Groundwater only
B. Surface water ANSWER
C. Reclaimed water
D. Blended water
SECTION 3: COAGULATION AND FLOCCULATION
21. The purpose of coagulation in water treatment is to:
A. Remove dissolved gases
B. Destabilize colloidal particles so they can clump together ANSWER
C. Kill pathogens
D. Remove hardness
22. The most common coagulant used in water treatment is:
A. Lime
B. Soda ash
C. Alum (aluminum sulfate) ANSWER
