NGWA GENERAL DRILLING EXAM 300 ACTUAL
QUESTIONS AND CORRECT ANSWERS WITH
RATIONALE ALREADY GRADED A+ LATEST UPDATE
ASSURED PASS
This comprehensive 300-question bank for the NGWA General Drilling Exam
covers all essential topics including drilling methods (cable tool, air rotary,
mud rotary), well design and construction, casing and screen selection,
grouting and annular seals, pump installation, well development, aquifer
hydraulics, groundwater protection, safety procedures, and NGWA
certification requirements. Each unique question includes multiple-choice
options, a correct answer, and a detailed evidence-based rationale. Topics
address regulatory compliance, formation evaluation, drilling fluid functions,
well abandonment, pump systems, and water quality testing. This resource
reinforces core drilling knowledge, prepares candidates for NGWA
certification exams, and supports professional competency in water well
construction and groundwater management.
1. Artesian pressure is generally the result of what two factors?
A) Gravity and temperature
B) Gravity and confining beds
C) Temperature and pressure
D) Confining beds and rock porosity
Answer: B
Rationale: Artesian pressure is caused by gravity acting on water trapped between
confining beds, forcing water to rise above the aquifer level due to hydrostatic
pressure differences .
2. Which of the following statements is true about the origin of rocks?
A) Sandstones were once volcanic lava flows
B) Limestones contain fossils because they were once shallow sea bottoms
C) Shales were formed from compressed sand
D) Granite is a sedimentary rock
,Answer: B
Rationale: Limestones often contain fossils because they formed from the
accumulation of marine organisms on ancient shallow sea floors .
3. Sandstones were originally formed from what type of deposits?
A) Volcanic ash
B) Ancient sand deposits such as river, beach, or dune sands
C) Compressed clay beds
D) Organic marine remains
Answer: B
Rationale: Sandstones are sedimentary rocks formed from compressed sand
deposits that accumulated in rivers, beaches, or dunes over geologic time .
4. What were shales originally formed from?
A) Sand deposits
B) Volcanic lava
C) Ancient clay beds
D) Marine fossils
Answer: C
Rationale: Shales are sedimentary rocks formed from compacted clay deposits that
settled in ancient water bodies .
5. To what depth can sedimentary formations extend?
A) Several hundred feet
B) One mile or more
C) Only surface level
D) 500 feet maximum
Answer: B
Rationale: Sedimentary formations can reach depths of a mile or more, containing
important groundwater resources and fossil fuel deposits .
6. The three main types of rock are:
A) Sandstone, limestone, and shale
B) Igneous, sedimentary, and metamorphic
C) Granite, basalt, and pumice
D) Clastic, chemical, and organic
Answer: B
Rationale: The three major rock classifications are igneous (formed from cooled
magma), sedimentary (formed from compressed sediments), and metamorphic
(formed from existing rocks altered by heat and pressure) .
,7. In which type of geological formation would water be least likely found?
A) Sandstone
B) Limestone
C) Granite
D) Alluvium
Answer: C
Rationale: Granite is an igneous rock with low porosity and permeability, making
it an unlikely source of groundwater compared to sedimentary formations .
8. True or false: Ground water, like surface water, has a tendency to flow downhill.
A) True
B) False
Answer: A
Rationale: Groundwater flows from areas of higher hydraulic head to lower head,
generally following the slope of the water table, similar to surface water flow .
9. Approximately what percentage of our nation's fresh water is underground?
A) Less than 50%
B) More than 90%
C) About 75%
D) About 25%
Answer: B
Rationale: More than 90% of available fresh water in the United States is stored
underground in aquifers, making groundwater a critical resource .
10. What is the most important safety step prior to setting up the rig?
A) Checking the weather forecast
B) Ensuring there are no overhead power lines within 20 feet of the mast
C) Testing the drilling fluid
D) Reviewing the well design
Answer: B
Rationale: Overhead power lines pose a serious electrocution hazard. Regulations
require maintaining a minimum clearance of 20 feet between the mast and any
power lines .
11. Which of the following should be done prior to setting the rig? (Select all that
apply)
A) Locate all buried materials
B) Verify you are on the correct property
, C) Confirm meeting setback requirements
D) All of the above
Answer: D
Rationale: Proper site preparation includes locating buried utilities, confirming
property ownership, and ensuring compliance with regulatory setbacks to prevent
damage and legal issues .
12. Confined space entry rules require which of the following?
A) Shoring of trench walls over 4 feet deep
B) Establishment of a buddy system
C) Atmospheric testing
D) All of the above
Answer: D
Rationale: Confined space safety requires shoring for deep trenches, a buddy
system for emergency response, and atmospheric testing to detect hazardous gases
.
13. In setting up and leveling the rig, the correct procedure includes:
A) Using suitable jack pads for stabilization
B) Position rig for minimum leveling
C) Have driller's assistant check jacks as operator levels rig
D) All of the above
Answer: D
Rationale: Proper rig setup includes using jack pads for stability, minimizing
leveling adjustments, and having an assistant verify jacks while leveling for safety
.
14. A well may be used as a sewage disposal site only if it is cased to the bottom of
the borehole.
A) True
B) False
Answer: B
Rationale: Using wells for sewage disposal is prohibited regardless of casing, as it
poses a serious risk of groundwater contamination .
15. Chain and drive shaft guards should be:
A) Removed for maintenance only
B) Kept in place at all times
C) Inspected monthly
D) Painted for visibility
QUESTIONS AND CORRECT ANSWERS WITH
RATIONALE ALREADY GRADED A+ LATEST UPDATE
ASSURED PASS
This comprehensive 300-question bank for the NGWA General Drilling Exam
covers all essential topics including drilling methods (cable tool, air rotary,
mud rotary), well design and construction, casing and screen selection,
grouting and annular seals, pump installation, well development, aquifer
hydraulics, groundwater protection, safety procedures, and NGWA
certification requirements. Each unique question includes multiple-choice
options, a correct answer, and a detailed evidence-based rationale. Topics
address regulatory compliance, formation evaluation, drilling fluid functions,
well abandonment, pump systems, and water quality testing. This resource
reinforces core drilling knowledge, prepares candidates for NGWA
certification exams, and supports professional competency in water well
construction and groundwater management.
1. Artesian pressure is generally the result of what two factors?
A) Gravity and temperature
B) Gravity and confining beds
C) Temperature and pressure
D) Confining beds and rock porosity
Answer: B
Rationale: Artesian pressure is caused by gravity acting on water trapped between
confining beds, forcing water to rise above the aquifer level due to hydrostatic
pressure differences .
2. Which of the following statements is true about the origin of rocks?
A) Sandstones were once volcanic lava flows
B) Limestones contain fossils because they were once shallow sea bottoms
C) Shales were formed from compressed sand
D) Granite is a sedimentary rock
,Answer: B
Rationale: Limestones often contain fossils because they formed from the
accumulation of marine organisms on ancient shallow sea floors .
3. Sandstones were originally formed from what type of deposits?
A) Volcanic ash
B) Ancient sand deposits such as river, beach, or dune sands
C) Compressed clay beds
D) Organic marine remains
Answer: B
Rationale: Sandstones are sedimentary rocks formed from compressed sand
deposits that accumulated in rivers, beaches, or dunes over geologic time .
4. What were shales originally formed from?
A) Sand deposits
B) Volcanic lava
C) Ancient clay beds
D) Marine fossils
Answer: C
Rationale: Shales are sedimentary rocks formed from compacted clay deposits that
settled in ancient water bodies .
5. To what depth can sedimentary formations extend?
A) Several hundred feet
B) One mile or more
C) Only surface level
D) 500 feet maximum
Answer: B
Rationale: Sedimentary formations can reach depths of a mile or more, containing
important groundwater resources and fossil fuel deposits .
6. The three main types of rock are:
A) Sandstone, limestone, and shale
B) Igneous, sedimentary, and metamorphic
C) Granite, basalt, and pumice
D) Clastic, chemical, and organic
Answer: B
Rationale: The three major rock classifications are igneous (formed from cooled
magma), sedimentary (formed from compressed sediments), and metamorphic
(formed from existing rocks altered by heat and pressure) .
,7. In which type of geological formation would water be least likely found?
A) Sandstone
B) Limestone
C) Granite
D) Alluvium
Answer: C
Rationale: Granite is an igneous rock with low porosity and permeability, making
it an unlikely source of groundwater compared to sedimentary formations .
8. True or false: Ground water, like surface water, has a tendency to flow downhill.
A) True
B) False
Answer: A
Rationale: Groundwater flows from areas of higher hydraulic head to lower head,
generally following the slope of the water table, similar to surface water flow .
9. Approximately what percentage of our nation's fresh water is underground?
A) Less than 50%
B) More than 90%
C) About 75%
D) About 25%
Answer: B
Rationale: More than 90% of available fresh water in the United States is stored
underground in aquifers, making groundwater a critical resource .
10. What is the most important safety step prior to setting up the rig?
A) Checking the weather forecast
B) Ensuring there are no overhead power lines within 20 feet of the mast
C) Testing the drilling fluid
D) Reviewing the well design
Answer: B
Rationale: Overhead power lines pose a serious electrocution hazard. Regulations
require maintaining a minimum clearance of 20 feet between the mast and any
power lines .
11. Which of the following should be done prior to setting the rig? (Select all that
apply)
A) Locate all buried materials
B) Verify you are on the correct property
, C) Confirm meeting setback requirements
D) All of the above
Answer: D
Rationale: Proper site preparation includes locating buried utilities, confirming
property ownership, and ensuring compliance with regulatory setbacks to prevent
damage and legal issues .
12. Confined space entry rules require which of the following?
A) Shoring of trench walls over 4 feet deep
B) Establishment of a buddy system
C) Atmospheric testing
D) All of the above
Answer: D
Rationale: Confined space safety requires shoring for deep trenches, a buddy
system for emergency response, and atmospheric testing to detect hazardous gases
.
13. In setting up and leveling the rig, the correct procedure includes:
A) Using suitable jack pads for stabilization
B) Position rig for minimum leveling
C) Have driller's assistant check jacks as operator levels rig
D) All of the above
Answer: D
Rationale: Proper rig setup includes using jack pads for stability, minimizing
leveling adjustments, and having an assistant verify jacks while leveling for safety
.
14. A well may be used as a sewage disposal site only if it is cased to the bottom of
the borehole.
A) True
B) False
Answer: B
Rationale: Using wells for sewage disposal is prohibited regardless of casing, as it
poses a serious risk of groundwater contamination .
15. Chain and drive shaft guards should be:
A) Removed for maintenance only
B) Kept in place at all times
C) Inspected monthly
D) Painted for visibility
