Minnesota Class D Water Exam questions and correct
answers (verified answers) q& a 2026-2027|instant
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1. What is the primary purpose of a public water system?
A. To provide recreational water use
B. To supply safe drinking water to the public
C. To increase wastewater production
D. To control stormwater runoff
Correct Answer: B. To supply safe drinking water to the public
Rationale: Public water systems are designed to provide water
that meets health standards for human consumption.
2. Which agency regulates drinking water standards in
Minnesota?
A. Minnesota Department of Transportation
B. Minnesota Department of Agriculture
C. Minnesota Department of Health
D. Environmental Protection Agency only
Correct Answer: C. Minnesota Department of Health
Rationale: The Minnesota Department of Health (MDH)
regulates public drinking water systems in the state.
,3. What is the main goal of water treatment?
A. Increase water hardness
B. Remove contaminants and pathogens
C. Add pollutants
D. Reduce water availability
Correct Answer: B. Remove contaminants and pathogens
Rationale: Treatment processes remove harmful substances
and microorganisms to make water safe.
4. Which process removes suspended particles from water?
A. Filtration
B. Chlorination
C. Aeration
D. Disinfection
Correct Answer: A. Filtration
Rationale: Filtration physically removes suspended solids and
particles from treated water.
5. What is the purpose of disinfecting drinking water?
A. Remove color only
B. Kill or inactivate disease-causing organisms
C. Increase turbidity
D. Add minerals
Correct Answer: B. Kill or inactivate disease-causing organisms
, Rationale: Disinfection prevents waterborne diseases by
controlling bacteria, viruses, and other pathogens.
6. Which chemical is commonly used for drinking water
disinfection?
A. Chlorine
B. Nitrogen
C. Carbon dioxide
D. Calcium carbonate
Correct Answer: A. Chlorine
Rationale: Chlorine is widely used because it effectively
destroys microorganisms and provides residual protection.
7. What does pH measure?
A. Water temperature
B. Acidity or alkalinity
C. Turbidity level
D. Chlorine concentration
Correct Answer: B. Acidity or alkalinity
Rationale: pH indicates whether water is acidic, neutral, or
alkaline.
8. A pH value of 7 indicates water is:
A. Acidic
answers (verified answers) q& a 2026-2027|instant
download pdf
1. What is the primary purpose of a public water system?
A. To provide recreational water use
B. To supply safe drinking water to the public
C. To increase wastewater production
D. To control stormwater runoff
Correct Answer: B. To supply safe drinking water to the public
Rationale: Public water systems are designed to provide water
that meets health standards for human consumption.
2. Which agency regulates drinking water standards in
Minnesota?
A. Minnesota Department of Transportation
B. Minnesota Department of Agriculture
C. Minnesota Department of Health
D. Environmental Protection Agency only
Correct Answer: C. Minnesota Department of Health
Rationale: The Minnesota Department of Health (MDH)
regulates public drinking water systems in the state.
,3. What is the main goal of water treatment?
A. Increase water hardness
B. Remove contaminants and pathogens
C. Add pollutants
D. Reduce water availability
Correct Answer: B. Remove contaminants and pathogens
Rationale: Treatment processes remove harmful substances
and microorganisms to make water safe.
4. Which process removes suspended particles from water?
A. Filtration
B. Chlorination
C. Aeration
D. Disinfection
Correct Answer: A. Filtration
Rationale: Filtration physically removes suspended solids and
particles from treated water.
5. What is the purpose of disinfecting drinking water?
A. Remove color only
B. Kill or inactivate disease-causing organisms
C. Increase turbidity
D. Add minerals
Correct Answer: B. Kill or inactivate disease-causing organisms
, Rationale: Disinfection prevents waterborne diseases by
controlling bacteria, viruses, and other pathogens.
6. Which chemical is commonly used for drinking water
disinfection?
A. Chlorine
B. Nitrogen
C. Carbon dioxide
D. Calcium carbonate
Correct Answer: A. Chlorine
Rationale: Chlorine is widely used because it effectively
destroys microorganisms and provides residual protection.
7. What does pH measure?
A. Water temperature
B. Acidity or alkalinity
C. Turbidity level
D. Chlorine concentration
Correct Answer: B. Acidity or alkalinity
Rationale: pH indicates whether water is acidic, neutral, or
alkaline.
8. A pH value of 7 indicates water is:
A. Acidic
