Licensing Exam Practice Test Questions

State Water Distribution Operator Class A 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 disinfect water
• To treat raw water
• To deliver safe, potable water to consumers
• To store treated water

Rationale: Distribution systems exist to transport safe, finished water from

treatment to end users.

• Which type of pipe material is most commonly used for large

transmission mains? 1 / 4

A. PVC

• Copper
• Ductile iron
• Lead

Rationale: Ductile iron has high strength and durability for large mains.

• What does SCADA stand for?
• System Control and Data Acquisition
• Supervisory Calibration and Data Automation
• Supervisory Control and Data Acquisition
• System Control and Distribution Automation

Rationale: SCADA = Supervisory Control and Data Acquisition, used for

monitoring systems.

• What is the typical chlorine residual required in a distribution system?
• 0.05 mg/L
• 0.1 mg/L
• 0.2 mg/L
• 2.0 mg/L

Rationale: Most states require a detectable residual, typically ≥ 0.2 mg/L

free chlorine.

• / 4

• What is the minimum pressure required in a distribution system under

normal conditions?

• 10 psi
• 20 psi
• 25 psi
• 35 psi

Rationale: Standard design maintains at least 35 psi to ensure service and

prevent contamination.

• What is the function of an air-release valve?
• To add oxygen
• To remove trapped air from pipelines
• To flush sediment
• To regulate pressure

Rationale: Trapped air reduces flow and pressure; air valves release it.

• What is the main cause of water hammer?
• High chlorine
• Sudden changes in water velocity
• Corrosion
• Low flow 3 / 4

Rationale: Fast valve closures or pump starts cause pressure surges called

water hammer.

• What is the standard fire-flow requirement in most municipal systems?
• 100 gpm
• 250 gpm
• 500 gpm
• 1,000 gpm

Rationale: Class A systems typically design for ~1,000 gpm for fire

protection.

9. A cross-connection is defined as:

• A leak in a pipe
• A physical connection between potable and non-potable sources
• A water meter bypass
• A hydrant connection

Rationale: Cross-connections pose contamination risks and require

prevention devices.

• Which device prevents backflow?
• / 4