Lesson plan Grade 7 Careers & CTE
Where a Water Rate Increase Goes: Keswick's Bill and Its Jobs
A 45-minute grade 7 careers lesson where students compute the percent increase on a fictional town's water bill and trace how the revenue pays the utility's workers.
Objectives
- Students will calculate the percent increase between an old and a new water bill.
- Students will explain how water-rate revenue pays for the utility's workforce and repairs.
Vocabulary
Key words: rate increase, revenue, percent increase
Teacher overview
When a town raises water rates, the added money pays for the people and repairs that keep water safe. This lesson uses Keswick, a fictional town proposing a rate increase, to teach percent increase and to connect that math to real jobs. A common misconception this lesson corrects is that a rate increase is pure profit, when in fact operators, technicians, and pipe repairs are paid out of that revenue.
Procedure
Hook (5 min): Ask students where they think the money from a water bill goes. Collect three or four guesses on the board without judging them. Then state that today's fictional town, Keswick, has proposed raising its typical monthly water bill, and the class will figure out by how much and why.
Direct instruction with worked example (12 min): Explain that a percent increase compares the size of a change to the starting amount, using the formula percent increase = (increase ÷ original) × 100. Model it with Keswick's typical bill: it would rise from $40 to $46 per month. Show every step. The increase is $46 − $40 = $6. Then $6 ÷ $40 = 0.15, and 0.15 × 100 = 15 percent. Say plainly where the added revenue goes: Keswick's utility lists operator wages, a new instrumentation and SCADA technician, and pipe repairs as the reasons for the increase. For context, combined US water and sewer bills rose about 24 percent from 2019 to 2024 and about 5.1 percent in 2025.
Guided practice (13 min): In pairs, students find the percent increase for a smaller household whose Keswick bill would rise from $25 to $28. Walk the room and check that pairs subtract first, then divide by the original ($3 ÷ $25 = 0.12, or 12 percent). As a check for understanding, ask two pairs to explain why they divide by the original bill, not the new one; look for the idea that the change is measured against the starting point.
Independent practice (10 min): Each student completes two handout items. First, find the whole-year dollar increase for the typical bill, which rises $6 per month. Second, in two sentences, explain one way the rate increase could help residents and one way it could strain a household on a tight budget.
Closure / exit ticket (5 min): On an index card, students find the percent increase for a bill that rises from $60 to $63, and name one job the added revenue helps pay. Collect and scan for the correct method before dismissal.
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. The typical bill rises from $40 to $46, so the increase is $6. Then $6 ÷ $40 = 0.15, and 0.15 × 100 = 15 percent.
- Answer: 12 percent. The smaller household's bill rises from $25 to $28, an increase of $3. Then $3 ÷ $25 = 0.12, and 0.12 × 100 = 12 percent.
- Answer: 72 dollars per year. The typical bill rises $6 per month, and $6 × 12 months = 72 dollars over a year.
- Answer: Accept any reasonable pair of ideas. Help: the revenue pays operators, a SCADA technician, and pipe repairs that keep water safe. Strain: a higher monthly bill is harder for a household on a tight budget to afford.
- Exit-ticket answer: 5 percent. The bill rises from $60 to $63, an increase of $3, and $3 ÷ $60 = 0.05, or 5 percent. Named jobs may include operator, SCADA technician, or repair crew.
Differentiation
Support
Give students a partially worked template that already shows the subtraction step, so they only divide and multiply. Provide a printed reminder of the order: subtract first, then divide by the original, then multiply by 100.
Extension
Ask students to compare Keswick's 15 percent increase to the roughly 24 percent national rise from 2019 to 2024, and write whether Keswick's proposed jump is larger or smaller than the national trend over that period, with one sentence of reasoning.
ELL supports
Pre-teach "rate increase," "revenue," and "percent increase" with a labeled example. Provide a sentence frame for the reasoning item: "The increase helps residents because ___, but it can strain a household because ___."