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

WD equipment: installation: practice questions

Our Water/Wastewater Operator bank has 9 questions on this topic. Here are 5 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

Why is new pipe kept capped and clean during installation?

  1. Capping the pipe keeps it warm so the gaskets seal faster after installation
  2. To speed up the job
  3. Dirt, animals and trench water can contaminate the main
  4. To keep the pipe warm so joints seal faster
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C. Dirt, animals and trench water can contaminate the main — Contamination makes disinfection harder.

Question 2 · Water Distribution Class I

What is a service tap?

  1. A storage tank outlet
  2. A hydrant valve used for flushing at the end of a main
  3. A connection drilled into a main to supply a customer service line
  4. A hydrant valve installed at the end of a main for flushing and fire flow testing
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C. A connection drilled into a main to supply a customer service line — Wet taps are done under pressure.

Question 3 · Water Distribution Class I

Why are new mains pressure tested before backfilling joints, where practical?

  1. To measure flow
  2. To clean the pipe and raise the water quality before backfilling
  3. To find leaks while joints are still exposed
  4. To raise water quality
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C. To find leaks while joints are still exposed — Pressure and leakage testing per AWWA.

Question 4 · Water Distribution Class I

What bedding is generally placed under water pipe in a trench?

  1. Large boulders spaced along the trench to support each joint
  2. Uniform, compacted bedding free of large rocks
  3. Nothing; pipe lies on any soil
  4. Large boulders for support
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B. Uniform, compacted bedding free of large rocks — Ten States Standards 8.7.2.

Question 5 · Water Distribution Class I

What common chlorine dose is used to disinfect new mains by the continuous-feed method?

  1. About 500 mg/L for 1 minute
  2. About 0.2 mg/L for 1 hour, the same as normal distribution residual
  3. About 25 mg/L, with a residual of at least 10 mg/L after 24 hours
  4. About 4 mg/L for 5 minutes
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C. About 25 mg/L, with a residual of at least 10 mg/L after 24 hours — AWWA C651 continuous-feed method.

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