NGWA Jetting and Driving Wells
Certification Exam (Exam H) Practice
Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. What is the primary purpose of jetting in well construction?
A. To pump water from the aquifer
B. To fracture rock formations
C. To loosen and remove soil around the well casing
D. To disinfect the well
Rationale: Jetting uses high-pressure water to loosen soil and aid the
installation of casing, not to pump water or fracture rock.
2. What type of soil is most suitable for driving wells using a jetting
method?
A. Solid bedrock
, B. Sandy or loose soils
C. Clay with high plasticity
D. Frozen ground
Rationale: Jetting works best in unconsolidated soils like sand, silt, or
gravel, which can be displaced by high-pressure water.
3. What is the common depth limit for a typical driven well in
unconsolidated formations?
A. 10 feet
B. 50 feet
C. 30 to 60 feet
D. 100 feet
Rationale: Driven wells are usually shallow, often ranging from 30 to
60 feet, depending on soil conditions.
4. Which material is most commonly used for driven well casings?
A. Copper
B. Steel or galvanized pipe
C. PVC
D. Aluminum
Rationale: Steel or galvanized pipe provides strength for driving and
resists collapse in loose soils.
5. What is the function of the well point in a jetting well system?
A. To seal the well from contamination
B. To allow water to flow into the casing during jetting
, C. To disinfect the well
D. To measure water quality
Rationale: The well point, often a perforated or screened section at
the bottom of the casing, allows soil to be displaced while water
enters.
6. Why is a foot valve sometimes used in jetting wells?
A. To reduce sediment
B. To maintain prime in the pump
C. To prevent contamination
D. To measure flow rate
Rationale: A foot valve prevents backflow, keeping the jetting pump
primed and functional.
7. What is the typical diameter of a driven well?
A. 1 inch
B. 2 to 4 inches
C. 1.25 to 2 inches
D. 3 to 6 inches
Rationale: Driven wells are narrow, usually 1.25 to 2 inches in
diameter, which is suitable for small pumps and jetting.
8. Which of the following safety precautions is critical when driving
wells?
A. Wearing sandals
B. Using proper protective equipment to prevent injuries from pipe
, and tools
C. Operating without supervision
D. Ignoring nearby utilities
Rationale: Safety gear such as gloves, boots, and eye protection is
essential when handling heavy pipes and driving equipment.
9. What type of pump is often used to provide high-pressure water for
jetting?
A. Centrifugal pump
B. Piston or jet pump
C. Submersible pump
D. Diaphragm pump
Rationale: Piston or jet pumps can generate the high pressures
needed to loosen soil during jetting operations.
10. What is the primary limitation of driven wells in terms of aquifer
selection?
A. Only suitable for artesian aquifers
B. Cannot penetrate deep, confined aquifers
C. Only works in clay aquifers
D. Works only with rock formations
Rationale: Driven wells are shallow and suitable only for
unconsolidated, unconfined aquifers.
11. Which factor determines the driving depth of a well?
A. Water color
Certification Exam (Exam H) Practice
Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. What is the primary purpose of jetting in well construction?
A. To pump water from the aquifer
B. To fracture rock formations
C. To loosen and remove soil around the well casing
D. To disinfect the well
Rationale: Jetting uses high-pressure water to loosen soil and aid the
installation of casing, not to pump water or fracture rock.
2. What type of soil is most suitable for driving wells using a jetting
method?
A. Solid bedrock
, B. Sandy or loose soils
C. Clay with high plasticity
D. Frozen ground
Rationale: Jetting works best in unconsolidated soils like sand, silt, or
gravel, which can be displaced by high-pressure water.
3. What is the common depth limit for a typical driven well in
unconsolidated formations?
A. 10 feet
B. 50 feet
C. 30 to 60 feet
D. 100 feet
Rationale: Driven wells are usually shallow, often ranging from 30 to
60 feet, depending on soil conditions.
4. Which material is most commonly used for driven well casings?
A. Copper
B. Steel or galvanized pipe
C. PVC
D. Aluminum
Rationale: Steel or galvanized pipe provides strength for driving and
resists collapse in loose soils.
5. What is the function of the well point in a jetting well system?
A. To seal the well from contamination
B. To allow water to flow into the casing during jetting
, C. To disinfect the well
D. To measure water quality
Rationale: The well point, often a perforated or screened section at
the bottom of the casing, allows soil to be displaced while water
enters.
6. Why is a foot valve sometimes used in jetting wells?
A. To reduce sediment
B. To maintain prime in the pump
C. To prevent contamination
D. To measure flow rate
Rationale: A foot valve prevents backflow, keeping the jetting pump
primed and functional.
7. What is the typical diameter of a driven well?
A. 1 inch
B. 2 to 4 inches
C. 1.25 to 2 inches
D. 3 to 6 inches
Rationale: Driven wells are narrow, usually 1.25 to 2 inches in
diameter, which is suitable for small pumps and jetting.
8. Which of the following safety precautions is critical when driving
wells?
A. Wearing sandals
B. Using proper protective equipment to prevent injuries from pipe
, and tools
C. Operating without supervision
D. Ignoring nearby utilities
Rationale: Safety gear such as gloves, boots, and eye protection is
essential when handling heavy pipes and driving equipment.
9. What type of pump is often used to provide high-pressure water for
jetting?
A. Centrifugal pump
B. Piston or jet pump
C. Submersible pump
D. Diaphragm pump
Rationale: Piston or jet pumps can generate the high pressures
needed to loosen soil during jetting operations.
10. What is the primary limitation of driven wells in terms of aquifer
selection?
A. Only suitable for artesian aquifers
B. Cannot penetrate deep, confined aquifers
C. Only works in clay aquifers
D. Works only with rock formations
Rationale: Driven wells are shallow and suitable only for
unconsolidated, unconfined aquifers.
11. Which factor determines the driving depth of a well?
A. Water color
