NGWA WATER SYSTEMS CERTIFICATION EXAM (GREATER THAN 100 GPM – EXAM L)
QUESTIONS AND CORRECT ANSWERS (VERIFIED ANSWERS) PLUS RATIONALES 2026 Q&A |
INSTANT DOWNLOAD PDF.
CORE DOMAINS
1. Pump and Well Hydraulics for High-Capacity Systems
2. Water Well Construction and Borehole Design
3. Electrical Systems, Control Panels, and Motor Protection
4. Groundwater Hydrology and Aquifer Management
5. Water Quality, Treatment, and Disinfection Standards
6. Regulatory Compliance and Environmental Protection
7. Safety Protocols and Site Risk Management
8. Troubleshooting and Preventive Maintenance Procedures
INTRODUCTION
This comprehensive examination is designed to assess the technical proficiency, regulatory knowledg
SECTION ONE
What is the primary purpose of a pitless adapter in a well system?
A. To increase the total dynamic head of the system.
,B. To provide a sanitary, frost-free, underground connection to the distribution line.
C. To measure the discharge pressure of the pump.
D. To regulate the flow of water into the well casing.
🟢B
🔴 RATIONALE: A pitless adapter allows for a watertight, sanitary seal where the discharge pipe
connects to the well casing below the frost line, preventing freezing and contamination.
When calculating the Total Dynamic Head (TDH), which of the following is included?
A. Pump efficiency rating only.
B. Vertical lift, friction loss, and discharge pressure.
C. Only the depth to the static water level.
D. The diameter of the pump impeller.
🟢B
🔴 RATIONALE: TDH is the sum of the vertical lift from the pumping water level to the discharge
point, friction losses in the piping, and the required discharge pressure.
Which material is most commonly used for well screens in highly corrosive environments?
A. Galvanized steel.
B. PVC.
C. Stainless steel.
D. Carbon steel.
🟢C
🔴 RATIONALE: Stainless steel offers the highest resistance to corrosion, making it the preferred
choice for well screens in aggressive or corrosive groundwater conditions.
What happens to the motor current (amperage) if a pump operates against a closed discharge
valve?
A. It increases significantly.
,B. It decreases.
C. It remains constant.
D. It fluctuates rapidly.
🟢B
🔴 RATIONALE: For centrifugal pumps, as the flow rate decreases to zero (shut-off head), the
power consumption and current draw typically decrease because the pump is not doing work on the
water.
What is the standard purpose of a check valve in a submersible pump installation?
A. To maintain pump priming and prevent backflow when the pump stops.
B. To increase the flow rate of the pump.
C. To reduce the electrical demand of the motor.
D. To act as a safety pressure relief valve.
🟢A
🔴 RATIONALE: Check valves prevent water from flowing back down into the well when the pump
motor is turned off, thereby maintaining prime and preventing water hammer.
Which device is essential for protecting a three-phase motor from phase loss?
A. Overload relay.
B. Phase monitor relay.
C. Variable Frequency Drive (VFD) bypass.
D. Pressure transducer.
🟢B
🔴 RATIONALE: A phase monitor relay detects unbalanced voltages or the loss of a phase, which
would otherwise damage a three-phase motor by causing overheating.
What is the recommended minimum distance for a well from a septic tank?
A. 10 feet.
, B. 50 feet.
C. 100 feet.
D. 200 feet.
🟢C
🔴 RATIONALE: To prevent contamination from effluent, regulatory standards typically mandate a
minimum separation distance of 100 feet between a water well and a septic tank.
When developing a well, what is the primary goal of "surging"?
A. To increase the static water level.
B. To remove fine particles and drilling mud from the aquifer and filter pack.
C. To test the pump’s maximum capacity.
D. To cement the casing in place.
🟢B
🔴 RATIONALE: Surging uses the movement of water back and forth through the well screen to
break up mud and fines, drawing them into the well for removal, thereby improving well efficiency.
In a VFD-controlled system, what is the advantage of a "soft start"?
A. It eliminates the need for a pressure tank.
B. It reduces mechanical stress and electrical inrush current.
C. It allows the pump to run at higher than rated RPM.
D. It prevents the pump from ever cycling off.
🟢B
🔴 RATIONALE: Soft starts gradually increase the frequency to the motor, significantly reducing the
mechanical shock of startup and the high inrush current seen with direct-on-line starting.
Which of the following water quality parameters is most affected by aeration?
A. Dissolved oxygen.
B. Nitrate concentration.
QUESTIONS AND CORRECT ANSWERS (VERIFIED ANSWERS) PLUS RATIONALES 2026 Q&A |
INSTANT DOWNLOAD PDF.
CORE DOMAINS
1. Pump and Well Hydraulics for High-Capacity Systems
2. Water Well Construction and Borehole Design
3. Electrical Systems, Control Panels, and Motor Protection
4. Groundwater Hydrology and Aquifer Management
5. Water Quality, Treatment, and Disinfection Standards
6. Regulatory Compliance and Environmental Protection
7. Safety Protocols and Site Risk Management
8. Troubleshooting and Preventive Maintenance Procedures
INTRODUCTION
This comprehensive examination is designed to assess the technical proficiency, regulatory knowledg
SECTION ONE
What is the primary purpose of a pitless adapter in a well system?
A. To increase the total dynamic head of the system.
,B. To provide a sanitary, frost-free, underground connection to the distribution line.
C. To measure the discharge pressure of the pump.
D. To regulate the flow of water into the well casing.
🟢B
🔴 RATIONALE: A pitless adapter allows for a watertight, sanitary seal where the discharge pipe
connects to the well casing below the frost line, preventing freezing and contamination.
When calculating the Total Dynamic Head (TDH), which of the following is included?
A. Pump efficiency rating only.
B. Vertical lift, friction loss, and discharge pressure.
C. Only the depth to the static water level.
D. The diameter of the pump impeller.
🟢B
🔴 RATIONALE: TDH is the sum of the vertical lift from the pumping water level to the discharge
point, friction losses in the piping, and the required discharge pressure.
Which material is most commonly used for well screens in highly corrosive environments?
A. Galvanized steel.
B. PVC.
C. Stainless steel.
D. Carbon steel.
🟢C
🔴 RATIONALE: Stainless steel offers the highest resistance to corrosion, making it the preferred
choice for well screens in aggressive or corrosive groundwater conditions.
What happens to the motor current (amperage) if a pump operates against a closed discharge
valve?
A. It increases significantly.
,B. It decreases.
C. It remains constant.
D. It fluctuates rapidly.
🟢B
🔴 RATIONALE: For centrifugal pumps, as the flow rate decreases to zero (shut-off head), the
power consumption and current draw typically decrease because the pump is not doing work on the
water.
What is the standard purpose of a check valve in a submersible pump installation?
A. To maintain pump priming and prevent backflow when the pump stops.
B. To increase the flow rate of the pump.
C. To reduce the electrical demand of the motor.
D. To act as a safety pressure relief valve.
🟢A
🔴 RATIONALE: Check valves prevent water from flowing back down into the well when the pump
motor is turned off, thereby maintaining prime and preventing water hammer.
Which device is essential for protecting a three-phase motor from phase loss?
A. Overload relay.
B. Phase monitor relay.
C. Variable Frequency Drive (VFD) bypass.
D. Pressure transducer.
🟢B
🔴 RATIONALE: A phase monitor relay detects unbalanced voltages or the loss of a phase, which
would otherwise damage a three-phase motor by causing overheating.
What is the recommended minimum distance for a well from a septic tank?
A. 10 feet.
, B. 50 feet.
C. 100 feet.
D. 200 feet.
🟢C
🔴 RATIONALE: To prevent contamination from effluent, regulatory standards typically mandate a
minimum separation distance of 100 feet between a water well and a septic tank.
When developing a well, what is the primary goal of "surging"?
A. To increase the static water level.
B. To remove fine particles and drilling mud from the aquifer and filter pack.
C. To test the pump’s maximum capacity.
D. To cement the casing in place.
🟢B
🔴 RATIONALE: Surging uses the movement of water back and forth through the well screen to
break up mud and fines, drawing them into the well for removal, thereby improving well efficiency.
In a VFD-controlled system, what is the advantage of a "soft start"?
A. It eliminates the need for a pressure tank.
B. It reduces mechanical stress and electrical inrush current.
C. It allows the pump to run at higher than rated RPM.
D. It prevents the pump from ever cycling off.
🟢B
🔴 RATIONALE: Soft starts gradually increase the frequency to the motor, significantly reducing the
mechanical shock of startup and the high inrush current seen with direct-on-line starting.
Which of the following water quality parameters is most affected by aeration?
A. Dissolved oxygen.
B. Nitrate concentration.
