Worksheet Grade 7 Social Studies & Civics
Testing 250 Taps in the Kestermere Schools
A grade 7 worksheet on a fictional district's lead testing results, using percent shares and filter costs to help a school board set its priorities.
Objectives
- Students will calculate the percent of tested taps above an action level at four schools.
- Students will compare the cost of filtering taps with the cost of replacing them.
- Students will explain how a stricter action level changes a district's testing results.
Vocabulary
- Action level
- A trigger number in lead and copper testing. If too many homes test above this level, the utility must take steps like improving treatment and telling the public.
- Service line
- A service line is the small pipe that connects the water main under the street to the plumbing inside one home or building. It is the last leg of the trip water makes to your tap.
Also: parts per billion, priority, capital budget
Teacher overview
School buildings often hold the oldest plumbing a district owns, and water that sits in a drinking fountain overnight has hours to pick up metal from the pipes and fixtures it touches. Under federal rules the lead action level is 15 parts per billion and drops to 10 parts per billion in 2027. This worksheet gives students the testing results from four schools in a fictional township and asks them to find each building's share of taps above the level, price two responses, and advise the board on what to do first with a limited budget.
Student Worksheet
Kestermere Township is a fictional school district with four buildings. Last spring the district tested every drinking-water tap in all four schools against the stricter 10 parts per billion action level that takes effect in 2027. The table shows what the testing found.
| School | Taps tested | Taps above the action level |
|---|---|---|
| Linfold Middle School | 80 | 12 |
| Hobsbourne Elementary | 60 | 3 |
| Yalding High School | 90 | 9 |
| Wrenholt Early Learning Center | 20 | 6 |
Show your work for each item.
- At Linfold Middle School, 12 of the 80 taps tested were above the action level. What percent of that school's taps were above it?
- At Hobsbourne Elementary, 3 of 60 taps were above the level. What percent is that?
- At Yalding High School, 9 of 90 taps were above the level. What percent is that?
- At Wrenholt Early Learning Center, 6 of 20 taps were above the level. What percent is that?
- Across the district, 30 of the 250 taps tested were above the level. What percent of all tested taps is that?
- Which school had the largest share of taps above the level? Use your answers to items 1 through 4.
- A filter that fits on one tap costs $250. What would filters on all 30 taps cost?
- Replacing the fixture and the pipe behind one tap costs $900. What would that cost for all 30 taps?
- How much more would replacing all 30 taps cost than filtering all 30?
- The board has $10,000 set aside for replacements this year. How many taps can it replace at $900 each?
- The federal action level falls from 15 parts per billion to 10 parts per billion in 2027. Explain why a tap that passed under the old level might not pass under the new one.
- The board must choose between filters on all 30 taps and full replacement at a smaller number of taps. Give one reason a board might choose each option.
From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.
Answer Key
Answer: 15 percent.
12 divided by 80 is 0.15, which is 15 percent of the taps tested at Linfold.Answer: 5 percent.
3 divided by 60 is 0.05, which is 5 percent of the taps tested at Hobsbourne.Answer: 10 percent.
9 divided by 90 is 0.10, which is 10 percent of the taps tested at Yalding.Answer: 30 percent.
6 divided by 20 is 0.30, which is 30 percent of the taps tested at Wrenholt.Answer: 12 percent.
30 divided by 250 is 0.12, which is 12 percent of all taps tested in the district.Answer: Wrenholt Early Learning Center.
Wrenholt's 30 percent is higher than Linfold's 15 percent, Yalding's 10 percent, and Hobsbourne's 5 percent, even though Wrenholt tested the fewest taps of the four schools.Answer: $7,500.
30 taps times $250 for each filter is $7,500.Answer: $27,000.
30 taps times $900 for each full replacement is $27,000.Answer: $19,500.
$27,000 minus $7,500 is $19,500 more for replacement than for filters.Answer: 11 taps.
$10,000 divided by $900 is about 11.1, and the board cannot replace part of a tap, so it can complete 11 replacements for $9,900.Answer: the new level is stricter.
A tap measuring between 10 and 15 parts per billion passed under the old action level and fails under the new one, so the same tap and the same result can move the tap onto the district's list for action without the plumbing changing at all, and neither level means that lead below it is safe.Answer: Accept one reason for each option.
Reasons for filters include covering every affected tap this year at lower cost and protecting students while money is raised. Reasons for replacement include removing the source rather than treating the water, and avoiding the cost of changing filter cartridges on schedule for years.
Differentiation
Support (below grade level)
Give these students a version of the table for the fictional district with the first percent already worked out as a model, and allow calculators for every item. Provide a division frame that reads "taps above the level divided by taps tested."
Extension (above grade level)
Ask students to write a one-page recommendation to the fictional Kestermere board that spends exactly $10,000 on a mix of filters and replacements, states how many of each the plan buys, and explains which school the plan serves first and why.
ELL supports
Pre-teach "action level," "parts per billion," and "fixture" with a labeled drawing of a drinking fountain, the pipe behind it, and a filter. Provide the table with one row read aloud and modeled, and allow items 11 and 12 to be answered in two short sentences using a provided frame.