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Worksheet Grade 8 Social Studies & Civics

Who Can Afford the Water Bill in Selby Junction?

A grade 8 economics worksheet where students figure each household's water bill as a percent of income and compare it to the 4.5 percent high-burden mark.

Objectives

  1. Students will calculate a household's yearly water bill as a percent of its income.
  2. Students will compare bills to the high-burden threshold and explain what makes a water bill affordable or not.

Vocabulary

Key words: affordability, household income, high-burden threshold, assistance program

Teacher overview

The same water bill can be easy for one family to pay and a real hardship for another. This worksheet uses three households in the fictional town of Selby Junction to make that idea concrete. A widely used rule of thumb treats combined water and sewer costs above roughly 4.5 percent of household income as a high burden, so students compare each household's bill to that mark. The rule of thumb comes from adding two EPA benchmarks, 2.5 percent for drinking water and 2 percent for wastewater, although EPA has no single official cutoff. The scenario gives students a reason to see a percent of income, not a dollar amount alone, as a better measure of whether a bill is affordable.

Who Can Afford the Water Bill in Selby Junction? — Grade 8 Social Studies & Civics
Name: ____________________________ Date: ______________

Student Worksheet

In the fictional town of Selby Junction, three households pay the water utility every month. Use these figures for all items. A household's yearly bill is its monthly bill times 12. The high-burden threshold is 4.5 percent of yearly income.

  • Household A: monthly water bill $75; yearly income $60,000.
  • Household B: monthly water bill $90; yearly income $24,000.
  • Household C: monthly water bill $100; yearly income $18,000.
  1. Find Household A's yearly water bill.
  2. What percent of Household A's yearly income is its yearly water bill? Round to the nearest tenth of a percent.
  3. Find Household B's yearly water bill.
  4. What percent of Household B's yearly income is its yearly water bill? Round to the nearest tenth of a percent.
  5. Find Household C's yearly water bill.
  6. What percent of Household C's yearly income is its yearly water bill? Round to the nearest tenth of a percent.
  7. Which households are at or above the 4.5 percent high-burden threshold?
  8. Household C's yearly bill is $300 more than Household A's, yet the gap in burden is much larger than $300 makes it sound. Explain why, using your percent answers from items 2 and 6.
  9. Selby Junction offers Household C an assistance program that cuts its bill by 25 percent. Find Household C's new yearly bill.
  10. What percent of Household C's yearly income is the new bill from item 9? Does the discount bring Household C below the 4.5 percent threshold?

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: $900 per year. $75 per month times 12 months equals $900.
  2. Answer: 1.5 percent. $900 divided by $60,000 equals 0.015, which is 1.5 percent.
  3. Answer: $1,080 per year. $90 per month times 12 months equals $1,080.
  4. Answer: 4.5 percent. $1,080 divided by $24,000 equals 0.045, which is 4.5 percent, right at the threshold.
  5. Answer: $1,200 per year. $100 per month times 12 months equals $1,200.
  6. Answer: 6.7 percent. $1,200 divided by $18,000 equals about 0.0667, which rounds to 6.7 percent.
  7. Answer: Households B and C. Household B sits at 4.5 percent and Household C is at 6.7 percent, so both meet or pass the threshold, while Household A at 1.5 percent does not.
  8. Answer: Burden depends on share of income, not dollars. Household A pays 1.5 percent of its income and Household C pays 6.7 percent, so the same water costs far more of what Household C has to live on, which the $300 difference in dollars hides.
  9. Answer: $900 per year. A 25 percent cut removes $300 from the $1,200 bill (1,200 times 0.25 equals 300), leaving $1,200 minus $300, which is $900.
  10. Answer: 5.0 percent. $900 divided by $18,000 equals 0.05, which is 5.0 percent, so the discount lowers the burden but still leaves Household C above the 4.5 percent threshold.

Differentiation

Support

Provide the division for items 2, 4, and 6 already set up (for example, "900 divided by 60,000 equals ___") so these students complete only the final step and the conversion to a percent. Allow a calculator throughout, and give a number line marked at 4.5 percent for item 7.

Extension

Ask students to find the exact monthly bill that would put Household C right at the 4.5 percent threshold, then explain in a sentence whether the 25 percent discount alone is enough to reach that target or whether the town would need to do more.

ELL supports

Pre-teach affordability, household income, and threshold with a simple bar graphic that shows a bill as a slice of total income. Provide a sentence frame for item 8: "The bill is a bigger burden for Household C because it takes ___ percent of its income, while it takes only ___ percent for Household A."