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NGWA (K) Water Systems < 100 GPM Final Exam
ALL 200 QUESTIONS AND CORRECT ANSWERS
LATEST UPDATE THIS YEAR
NGWA (K) Water Systems Less Than 100 GPM Exam, written from fresh, related content and
covering the full scope of the title (hydrology, wells, pumps, hydraulics, electrical, treatment,
safety, codes, and maintenance).
Each question includes a clear rationale, exam-style.
NGWA (K) Water Systems < 100 GPM – MCQs (Batch 1)
Question 1
Which unit is most commonly used to measure water flow rate in small water systems?
A) Gallons per hour
B) Gallons per minute
C) Cubic meters per second
D) Pounds per square inch
Answer: B) Gallons per minute
Explanation: Small water systems, especially those under 100 GPM, typically express flow rate
in gallons per minute for pump sizing and system design.
Question 2
1
, Page 2 of 93
What factor primarily determines the sustainable yield of a well?
A) Pump horsepower
B) Aquifer recharge rate
C) Pipe diameter
D) Electrical supply
Answer: B) Aquifer recharge rate
Explanation: Sustainable yield depends on how quickly the aquifer replenishes water, not just
the pump’s capacity.
Question 3
Which condition occurs when pump inlet pressure drops below the vapor pressure of water?
A) Water hammer
B) Cavitation
C) Laminar flow
D) Turbulence
Answer: B) Cavitation
Explanation: Cavitation forms vapor bubbles that collapse inside the pump, causing noise,
vibration, and damage.
Question 4
2
, Page 3 of 93
What is the primary purpose of a pitless adapter?
A) Increase pump efficiency
B) Allow sanitary underground discharge below frost line
C) Reduce electrical load
D) Filter groundwater
Answer: B) Allow sanitary underground discharge below frost line
Explanation: Pitless adapters protect water lines from freezing and contamination while
maintaining a sealed wellhead.
Question 5
Which type of well is most common for residential water systems under 100 GPM?
A) Dug well
B) Driven well
C) Drilled well
D) Collector well
Answer: C) Drilled well
Explanation: Drilled wells are deeper, more reliable, and less susceptible to contamination than
dug or driven wells.
Question 6
3
, Page 4 of 93
What does drawdown represent in a pumping well?
A) Pump efficiency loss
B) Difference between static and pumping water levels
C) Aquifer thickness
D) Pipe friction loss
Answer: B) Difference between static and pumping water levels
Explanation: Drawdown measures how much the water level drops when the pump is
operating.
Question 7
Which flow condition typically exists in properly sized water distribution pipes?
A) Static flow
B) Laminar flow
C) Turbulent flow
D) Zero velocity
Answer: C) Turbulent flow
Explanation: Most water systems operate in turbulent flow, allowing efficient transport and
mixing.
Question 8
4
NGWA (K) Water Systems < 100 GPM Final Exam
ALL 200 QUESTIONS AND CORRECT ANSWERS
LATEST UPDATE THIS YEAR
NGWA (K) Water Systems Less Than 100 GPM Exam, written from fresh, related content and
covering the full scope of the title (hydrology, wells, pumps, hydraulics, electrical, treatment,
safety, codes, and maintenance).
Each question includes a clear rationale, exam-style.
NGWA (K) Water Systems < 100 GPM – MCQs (Batch 1)
Question 1
Which unit is most commonly used to measure water flow rate in small water systems?
A) Gallons per hour
B) Gallons per minute
C) Cubic meters per second
D) Pounds per square inch
Answer: B) Gallons per minute
Explanation: Small water systems, especially those under 100 GPM, typically express flow rate
in gallons per minute for pump sizing and system design.
Question 2
1
, Page 2 of 93
What factor primarily determines the sustainable yield of a well?
A) Pump horsepower
B) Aquifer recharge rate
C) Pipe diameter
D) Electrical supply
Answer: B) Aquifer recharge rate
Explanation: Sustainable yield depends on how quickly the aquifer replenishes water, not just
the pump’s capacity.
Question 3
Which condition occurs when pump inlet pressure drops below the vapor pressure of water?
A) Water hammer
B) Cavitation
C) Laminar flow
D) Turbulence
Answer: B) Cavitation
Explanation: Cavitation forms vapor bubbles that collapse inside the pump, causing noise,
vibration, and damage.
Question 4
2
, Page 3 of 93
What is the primary purpose of a pitless adapter?
A) Increase pump efficiency
B) Allow sanitary underground discharge below frost line
C) Reduce electrical load
D) Filter groundwater
Answer: B) Allow sanitary underground discharge below frost line
Explanation: Pitless adapters protect water lines from freezing and contamination while
maintaining a sealed wellhead.
Question 5
Which type of well is most common for residential water systems under 100 GPM?
A) Dug well
B) Driven well
C) Drilled well
D) Collector well
Answer: C) Drilled well
Explanation: Drilled wells are deeper, more reliable, and less susceptible to contamination than
dug or driven wells.
Question 6
3
, Page 4 of 93
What does drawdown represent in a pumping well?
A) Pump efficiency loss
B) Difference between static and pumping water levels
C) Aquifer thickness
D) Pipe friction loss
Answer: B) Difference between static and pumping water levels
Explanation: Drawdown measures how much the water level drops when the pump is
operating.
Question 7
Which flow condition typically exists in properly sized water distribution pipes?
A) Static flow
B) Laminar flow
C) Turbulent flow
D) Zero velocity
Answer: C) Turbulent flow
Explanation: Most water systems operate in turbulent flow, allowing efficient transport and
mixing.
Question 8
4
