Exam Questions And Correct Answers

CA C57 Well Drilling Contractor Exam Questions And Correct Answers (Verified Answers) Plus Rationale2026 Q&A| Instant Download Pdf

• What is the primary purpose of a well casing?
• Increase water flow
• Prevent well collapse and contamination
• Heat the well water
• Reduce drilling cost

Rationale: Casing stabilizes the well walls and prevents surface

contaminants from entering.

• Which drilling method uses a rotating bit to crush rock?
• Cable tool
• Air rotary
• Rotary drilling
• Auger drilling

Rationale: Rotary drilling relies on a rotating drill bit to penetrate rock

formations.

• What is the common diameter range for residential water wells?
• 2–4 inches
• 4–8 inches
• 8–12 inches
• 12–16 inches

Rationale: Most residential wells are drilled between 4–8 inches in diameter

to accommodate pumps. 1 / 3

4. The primary function of a well screen is to:

• Increase water temperature
• Filter out sand and sediments
• Strengthen casing
• Lubricate the well

Rationale: Well screens prevent sand and debris from entering the pump

system.

• Which drilling method is most suitable for shallow, unconsolidated

formations?

• Rotary drilling
• Cable tool drilling
• Auger drilling
• Sonic drilling

Rationale: Auger drilling is effective for shallow soils and loose sediments.

6. When a well produces excessive sand, the likely cause is:

• Over-casing
• Improper screen selection or placement
• Using a submersible pump
• Low static water level

Rationale: Incorrect screens or placement allow sand to enter the well,

causing damage.

• What is the minimum clearance distance between a well and a septic

tank?

• 5 feet
• 10 feet
• 50 feet
• 100 feet

Rationale: To prevent contamination, wells should be sited at least 50 feet

from septic systems.

8. The term “static water level” refers to:

• Pumping water level 2 / 3

• Water level in a non-pumping well
• Maximum well depth
• Minimum pump height

Rationale: Static water level is the level of water in a well when it is not

being pumped.

• Which type of pump is commonly installed in deep wells?
• Centrifugal pump
• Submersible pump
• Jet pump
• Gear pump

Rationale: Submersible pumps are suitable for deep wells as they can push

water efficiently to the surface.

• What is the purpose of well development?
• Reduce water depth
• Remove drilling debris and improve flow
• Install casing
• Reduce pump energy

Rationale: Well development cleans the formation and ensures maximum

yield.

• Which drilling fluid is used in rotary drilling to lift cuttings?
• Air
• Foam
• Mud
• Water only

Rationale: Drilling mud transports cuttings to the surface and stabilizes the

borehole.

• What is the term for the natural flow of water to the surface

without pumping?

• Artesian flow
• Flowing well
• / 3