Well Driller / Water Well Drilling
Contractor Exam – Practice Test Questions
And Correct Answers (Verified Answers)
Plus Rationales 2026 Q&A | Instant
Download Pdf
1. What is the main purpose of a well screen?
A. To increase drilling speed
B. To prevent sand and sediment from entering the well
C. To support the casing
D. To reduce water table pressure
Answer: B
The well screen filters out sediment while allowing groundwater
to enter the well efficiently.
2. Which type of drilling method is most commonly used for deep
water wells in hard rock formations?
A. Cable tool drilling
B. Rotary drilling
C. Jetting
D. Auger drilling
Answer: B
Rotary drilling is effective for deep wells and can penetrate hard
rock using drilling mud and rotating bits.
,3. The static water level in a well is measured from:
A. The ground surface to the top of the casing
B. The top of the water column to the bottom of the well
C. The ground surface to the water surface in the well
D. The pump to the aquifer
Answer: C
Static water level is the distance from the ground surface down
to where water stands in the well when not pumping.
4. What is the primary function of drilling mud?
A. To lubricate the drill bit and remove cuttings
B. To seal fractures in the aquifer
C. To sterilize the borehole
D. To increase drilling torque
Answer: A
Drilling mud cools and lubricates the drill bit, carries cuFngs to
the surface, and stabilizes the borehole.
5. Which of the following aquifers is typically unconfined?
A. Artesian
B. Fractured rock
C. Water table
D. Perched
Answer: C
A water table aquifer is unconfined, meaning it is directly open
to surface recharge.
6. When grouting an annular space, what is the typical minimum
thickness recommended?
A. 1 inch
, B. 2 inches
C. 3 inches
D. 4 inches
Answer: C
A 3-inch annular space allows sufficient room for proper grout
placement and sealing.
7. Which material is commonly used for sanitary well seals?
A. Rubber gasket
B. Concrete plug
C. PVC glue
D. Epoxy resin
Answer: A
Rubber gaskets provide a tight, sanitary seal to prevent
contaminants from entering between casing and cap.
8. The drawdown in a well refers to:
A. The distance between static and pumping water levels
B. The diameter of the well casing
C. The total well depth
D. The change in discharge rate
Answer: A
Drawdown is how far the water level falls when the well is being
pumped.
9. Which of the following is most effective for disinfecting a new
well?
A. Salt water solution
B. Boiling water
C. Chlorine solution
Contractor Exam – Practice Test Questions
And Correct Answers (Verified Answers)
Plus Rationales 2026 Q&A | Instant
Download Pdf
1. What is the main purpose of a well screen?
A. To increase drilling speed
B. To prevent sand and sediment from entering the well
C. To support the casing
D. To reduce water table pressure
Answer: B
The well screen filters out sediment while allowing groundwater
to enter the well efficiently.
2. Which type of drilling method is most commonly used for deep
water wells in hard rock formations?
A. Cable tool drilling
B. Rotary drilling
C. Jetting
D. Auger drilling
Answer: B
Rotary drilling is effective for deep wells and can penetrate hard
rock using drilling mud and rotating bits.
,3. The static water level in a well is measured from:
A. The ground surface to the top of the casing
B. The top of the water column to the bottom of the well
C. The ground surface to the water surface in the well
D. The pump to the aquifer
Answer: C
Static water level is the distance from the ground surface down
to where water stands in the well when not pumping.
4. What is the primary function of drilling mud?
A. To lubricate the drill bit and remove cuttings
B. To seal fractures in the aquifer
C. To sterilize the borehole
D. To increase drilling torque
Answer: A
Drilling mud cools and lubricates the drill bit, carries cuFngs to
the surface, and stabilizes the borehole.
5. Which of the following aquifers is typically unconfined?
A. Artesian
B. Fractured rock
C. Water table
D. Perched
Answer: C
A water table aquifer is unconfined, meaning it is directly open
to surface recharge.
6. When grouting an annular space, what is the typical minimum
thickness recommended?
A. 1 inch
, B. 2 inches
C. 3 inches
D. 4 inches
Answer: C
A 3-inch annular space allows sufficient room for proper grout
placement and sealing.
7. Which material is commonly used for sanitary well seals?
A. Rubber gasket
B. Concrete plug
C. PVC glue
D. Epoxy resin
Answer: A
Rubber gaskets provide a tight, sanitary seal to prevent
contaminants from entering between casing and cap.
8. The drawdown in a well refers to:
A. The distance between static and pumping water levels
B. The diameter of the well casing
C. The total well depth
D. The change in discharge rate
Answer: A
Drawdown is how far the water level falls when the well is being
pumped.
9. Which of the following is most effective for disinfecting a new
well?
A. Salt water solution
B. Boiling water
C. Chlorine solution
