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Quiz & test questions Grade 6 Careers & CTE

Dunnholt Backflow Tester: A Water Careers Quiz

A grade 6 careers quiz on the cross-connection control specialist's job, mixing multiple choice, short answer, and percent and unit-rate computation.

Objectives

  1. Students will explain how a pressure drop in a water main can pull water backward out of a building.
  2. Students will calculate a tests-per-day unit rate and two percentages from a testing record.
  3. Students will describe how a person qualifies for certification as a backflow assembly tester.

Vocabulary

Cross-connection
A cross-connection is any place where drinking water pipes are linked to something dirty, like a garden hose left sitting in a bucket of soapy water. If the flow reverses, the dirty water can get sucked in.
Backflow
Backflow is water flowing backward through a pipe in the wrong direction, which can pull dirty water into the clean drinking water system. Special devices are installed on pipes to stop it.

Also: backflow prevention assembly, certification, unit rate

Teacher overview

This 30-minute quiz is worth 26 points and checks what students understand about the work of a cross-connection control specialist, the water department employee who keeps contamination inside buildings from reaching the pipes in the street. It mixes two multiple-choice items, two short-answer items, and four computation items, all drawn from one month of testing records in the fictional town of Dunnholt. One misconception is worth correcting before students begin. Many students assume water can move only one direction in a pipe, from the treatment plant toward the house, so backflow sounds impossible to them. Pressure decides direction, and when a main break or a large fire flow drops the pressure in the street, water can be pulled backward out of a building and into the public main.

Dunnholt Backflow Tester: A Water Careers Quiz — Grade 6 Careers & CTE
Name: ____________________________ Date: ______________

Assessment

The Dunnholt testing records. The fictional town of Dunnholt has one cross-connection control specialist on its water department staff. Her job is to find every place where a building could push water back into the town's pipes. A garden hose left sitting in a full mop bucket is one of those places. Boilers, car washes, and lawn sprinkler systems that use fertilizer are others. At each of those places the building owner must install a backflow preventer, and the larger connections, such as boilers, car washes, and sprinkler systems, need a testable backflow prevention assembly. The specialist tests every assembly once a year, writes a report on each one, and holds a state certification that she renews by exam. Show your work on every item that asks for a number.

Testing record for the month Value
Assemblies tested during the month 60
Days spent testing 5
Assemblies that failed the test 9
Assemblies on the town's full list 300
Assemblies tested so far this year 240
  1. (2 points) What does a backflow prevention assembly do?
    • A) It measures how much water a building uses each month.
    • B) It keeps water inside a building from flowing back into the town's pipes.
    • C) It raises the water pressure inside a building.
    • D) It removes lead from a building's pipes.
  2. (3 points) A fire crew opens a hydrant on the same street as a car wash, and the pressure in the main drops for several minutes. Explain in one or two sentences why that drop is a risk to the town's water.
  3. (4 points) The specialist tested 60 assemblies during 5 days of testing. How many assemblies is that per day?
  4. (4 points) Of the 60 assemblies tested that month, 9 failed. What percent of the tested assemblies failed?
  5. (4 points) The town's full list holds 300 assemblies. Using the rate you found in item 3, how many days of testing would the whole list take?
  6. (3 points) Which statement best describes how a person becomes a certified backflow assembly tester?
    • A) A four-year college degree is the only route into the work.
    • B) No training is needed, because the test is simple.
    • C) A person finishes high school, trains on the job or in a short course, and then passes a state certification exam.
    • D) Only a licensed doctor may test an assembly.
  7. (4 points) The specialist has tested 240 of the 300 assemblies on the list this year. What percent of the list is still untested?
  8. (2 points) Give one reason the town keeps a written report for every assembly, including the ones that pass.

From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.

Answer Key
  1. Answer: B.
    The assembly is a one-way barrier. It lets water into the building and blocks it from returning to the main. Choice A describes a meter, and choice D describes corrosion control or a filter.
  2. Answer: Accept any answer explaining that lower pressure in the main can pull water backward out of the car wash, so soap or dirty water could enter the pipes that serve other customers on the street.
  3. Answer: 12 assemblies per day.
    60 assemblies divided by 5 days equals 12 assemblies per day.
  4. Answer: 15 percent.
    9 divided by 60 equals 0.15, and 0.15 written as a percent is 15 percent.
  5. Answer: 25 days.
    300 assemblies divided by 12 assemblies per day equals 25 days of testing.
  6. Answer: C.
    Backflow assembly testers are certified by the state after training and an exam, and most enter the work with a high school diploma. Some come from a plumbing apprenticeship or a two-year water technology program, but none of those routes requires a four-year degree.
  7. Answer: 20 percent.
    300 minus 240 equals 60 assemblies still untested. 60 divided by 300 equals 0.2, which is 20 percent.
  8. Answer: Accept any answer noting that the report proves the test was done, gives the town a record to compare against next year, and shows an inspector which assemblies are protecting the public pipes.

Differentiation

Support

Give these students a version of the fictional Dunnholt record table that shows only the three rows needed for the item in front of them, and print items 3 and 5 with the division already set up. Allow a calculator throughout, and accept a labeled drawing instead of sentences for item 2.

Extension

Ask students to write the short notice the specialist would mail to a building owner whose assembly failed. The notice must state what failed, why the town cares, and how many days the owner has to schedule a repair test.

ELL supports

Pre-teach "cross-connection," "backflow," and "assembly" with a labeled drawing of a hose sitting in a bucket beside a picture of the fictional town's water main. Provide the sentence frame "When the pressure in the main drops, water can ____ because ____." Allow students to answer items 2 and 8 aloud before writing.

Extensions

Have students count the possible cross-connections in their own school, such as hose bibs, mop sinks, and boiler rooms, then compare that count with the 300 assemblies on the fictional Dunnholt list and estimate how many days a specialist would need for a district their size. Students can also write three interview questions for a local cross-connection specialist or plumbing inspector.