C Licensing Exam Practice Test

State Water Distribution Operator Class C Licensing Exam Practice Test Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• What is the primary purpose of a water distribution system?
• To treat raw water
• To provide irrigation only
• To deliver safe, reliable potable water to customers
• To monitor wastewater

Rationale: The distribution system’s core function is delivering treated,

potable water to end users safely and reliably.

2. The term “head loss” in pipelines refers to:

• Increase in pressure
• Water temperature drop
• Loss of energy due to friction 1 / 4

• Pipe corrosion

Rationale: Head loss is the reduction of pressure caused by friction

between water and pipe walls.

3. Most water distribution systems maintain system pressure above:

• 10 psi
• 20 psi
• 35 psi
• 5 psi

Rationale: Typical systems aim to keep pressures safely above 35 psi for

adequate service and fire protection.

4. The main reason for flushing hydrants is to:

• Reduce customer bills
• Remove sediment and improve water quality
• Increase chlorine demand
• Cool the hydrant

Rationale: Flushing removes accumulated sediments and maintains proper

water quality.

• A standard fire hydrant operating nut typically requires what tool?
• Pipe wrench
• Adjustable pliers
• Hydrant wrench
• Hammer 2 / 4

Rationale: Hydrant nuts are designed to be opened with a hydrant wrench

for safety and control.

• Which valve is most commonly used for isolating sections of distribution

mains?

• Foot valve
• Gate valve
• Air-release valve
• Check valve

Rationale: Gate valves allow full open/close and are widely used for line

isolation.

7. Water hammer is best described as:

• Low-pressure surge
• Routine fluctuation
• Sudden pressure spike from quick valve closure
• Air-release event

Rationale: Rapid changes in velocity cause severe pressure surges known

as water hammer.

• The most common pipe material used in small distribution systems

today is:

• Lead
• Cast iron

C. PVC 3 / 4

• Wood stave

Rationale: PVC is lightweight, corrosion-resistant, and cost-effective for

distribution mains.

9. Chlorine residual in a distribution system ensures:

• Water hardness
• High turbidity
• Reduced alkalinity
• Continued disinfection protection

Rationale: A chlorine residual provides ongoing microbial protection

throughout the system.

• Which instrument is used to measure pressure in water mains?
• Turbidimeter
• pH meter
• Pressure gauge
• Colorimeter

Rationale: Pressure gauges determine system pressure at various points.

CONTINUING (QUESTIONS 11–50)

• What does SCADA stand for?
• Supervisory Chemical Analysis Data Application
• Supervisory Control and Data Acquisition
• System Control and Distribution Automation
• / 4