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Water & Wastewater Operator (WPI/ABC Class I) — Practice Exam

WD equipment: maintenance: practice questions

Our Water/Wastewater Operator bank has 8 questions on this topic. Here are 4 of them with answers; the full mock exam draws from every topic, like the real one.

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Question 1 · Water Distribution Class I

What is pigging?

  1. Sending a foam or plastic plug through a main to scrape out deposits
  2. Disinfecting with tablets
  3. Disinfecting a new main with chlorine tablets glued inside each joint during installation
  4. Disinfecting a main with chlorine tablets placed at each joint
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A. Sending a foam or plastic plug through a main to scrape out deposits — Used to restore pipe capacity.

Question 2 · Water Distribution Class I

What is a sign that a pump's check valve is failing?

  1. Higher chlorine residual
  2. Higher flow, lower noise and a cooler motor than normal when the pump is running
  3. The motor draws less current at start-up
  4. The pump spins backward or the discharge pressure drops when it stops
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D. The pump spins backward or the discharge pressure drops when it stops — Maintain pump station check valves.

Question 3 · Water Distribution Class I

How are storage tanks typically cleaned and returned to service?

  1. Add extra chlorine through the hatch without draining the tank and keep it in service
  2. Paint the outside only
  3. Add extra chlorine without draining and keep the tank in service
  4. Drain, clean and inspect, disinfect following AWWA practice, and test before use
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D. Drain, clean and inspect, disinfect following AWWA practice, and test before use — Clean and disinfect finished water storage.

Question 4 · Water Distribution Class I

Why do customers sometimes see discolored water after hydrant flushing?

  1. Flushing adds color to the water from the paint inside the hydrant barrel
  2. Chlorine turns water brown
  3. Flushing stirs up sediment and iron deposits in the mains
  4. Flushing adds color to the water from the hydrant paint
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C. Flushing stirs up sediment and iron deposits in the mains — Notify customers before flushing.

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