Project Grade 9 Science
The Aldwinter High Water Audit: Finding the Standing Leak
A four-session grade 9 project where students meter their school's overnight water use, test one low-cost fix, and propose retrofits to a fictional facilities director.
Objectives
- Students will measure a building's overnight standing water use from meter readings.
- Students will measure fixture flow rates and identify the largest contributors to standing use.
- Students will test one change and report the measured effect in a written proposal.
Vocabulary
- Flow rate
- Flow rate measures how much water moves past a point in a certain amount of time, like gallons per minute through a garden hose. Bigger pipes and stronger pushes give bigger flow rates.
Also: standing use, aerator, flapper valve, baseline, retrofit
Teacher overview
Utilities find hidden leaks by watching what a meter does when nobody is using water, and a school building offers the same opportunity every night. Over four sessions, student teams read their school's water meter to establish an overnight baseline, inventory and time the fixtures, test one low-cost change, and then measure the same overnight window again. The driving question is whether the building is losing water while it is empty, and what it would cost to stop it. The deliverable is a written proposal with a data appendix, addressed to a fictional facilities director who has a small budget and no patience for estimates that are not measured.
Project Brief
Driving question. How much water does our school use when nobody is in the building, and what would it cost to reduce it?
Client. Your class is reporting to a fictional facilities director for the Aldwinter school district. She has a fictional budget of $1,500 for water-saving parts this year, and she has told you she will fund only changes that your own measurements support.
Why this matters. Leaks are quiet and steady, so they are easy to miss and expensive over a year. Household leaks alone waste an average of about 180 gallons per week, nearly 9,400 gallons per year, according to EPA WaterSense. A school has far more fixtures than a house, and it sits empty for about two thirds of every day.
Your hypothesis. Before you collect data, each team writes a testable hypothesis in this form: if the building's overnight water use comes mainly from leaking toilets rather than from dripping faucets, then fixing the leaking toilets will lower the overnight meter reading more than repairing dripping faucets will. Teams may write a different hypothesis, but it must name a suspected source and predict a measurable result.
The variable you test. In Session 3 your team changes exactly one thing in the building and holds everything else the same. The overnight standing use, in gallons per hour, is what you measure before and after.
Constraints. Your proposal must obey all four of these limits. First, the total parts cost must fit the fictional $1,500 budget. Second, you may only recommend work that a custodian can do without a licensed plumber, such as flapper valves, aerators, and cleaning. Third, every claim in the proposal must trace to a measurement your team recorded, not to a figure from the internet. Fourth, the change you test must be reversible by the end of the project.
The deliverable. Each team submits a four-page written proposal to the fictional facilities director containing a one-page summary with your recommendation, a page describing your method, a page of results with at least one table and one graph, and a data appendix with every raw reading. Teams present the summary page to the class in five minutes on the final day.
Data-recording plan. Every team keeps one shared data sheet with four columns: date and time, meter reading, who took the reading, and anything unusual happening in the building. Readings are taken at the end of the school day and at the start of the next school day, so each overnight window has a start and an end. Fixture measurements are recorded on a second sheet listing room number, fixture type, and the time to fill a one-gallon container.
Milestones
Session 1: Baseline and question. With your teacher and a custodian, locate the building meter and learn to read it. Record one afternoon reading and one next-morning reading. Compute the gallons used overnight and divide by the number of hours to get the standing use in gallons per hour. Write your team's hypothesis. Checkable output: a completed baseline data sheet and a one-paragraph hypothesis.
Session 2: Fixture inventory and flow rates. Walk an assigned wing and list every sink, toilet, urinal, and drinking fountain by room number. Time how long each faucet takes to fill a one-gallon container and convert that to gallons per minute. Check each closed faucet for drips and record the drips per minute. Have the custodian lift each toilet tank lid, put ten drops of food coloring in the tank, wait fifteen minutes without flushing, and record which bowls show color, since color in the bowl means a leaking flapper valve. If the toilets are tankless flushometer models, listen for running water and watch the bowl for a steady trickle instead, and note the fixture type. Wash your hands after working in the restrooms. Checkable output: a fixture table with a flow rate and drip count for every faucet and a leak result for every toilet.
Session 3: Test one change. Choose the single change your hypothesis points to, get it approved by your teacher and the custodian, and install it with the custodian. Record exactly what was changed, in which rooms, and at what time. Take an afternoon reading and a next-morning reading in the same way as Session 1. Checkable output: a change log and a second overnight standing-use figure calculated the same way as the first.
Session 4: Proposal and presentation. Compare your two standing-use figures and make a graph of them. Decide whether your hypothesis was supported, and say so plainly even if it was not. Price the parts for the full building using the same parts you tested and check the total against the fictional budget. Checkable output: the four-page proposal, the five-minute presentation, and a written answer to this question: what would you measure next if you had one more week?
From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.
Rubric
| Criterion | Emerging | Developing | Proficient | Advanced |
|---|---|---|---|---|
| Measurement quality | Readings are missing, undated, or taken inconsistently | Most readings are present but the overnight windows differ in length without adjustment | Readings are complete, timed consistently, and converted correctly to gallons per hour | Readings are complete and consistent, and the team notes and accounts for events that could distort a window |
| Testing the variable | More than one thing changed, or the change is not documented | One change made but the change log is incomplete | Exactly one change made, fully logged, with before and after measured the same way | One change made and logged, measured identically before and after, with a stated reason the comparison is fair |
| Use of evidence in the proposal | Recommendation is not supported by team data | Recommendation cites data but interprets it loosely | Every claim traces to a recorded measurement, and the results table and graph match the text | Claims trace to measurements, and the proposal states how confident the team is and why |
| Meeting the constraints | Proposal exceeds the budget or requires a licensed plumber | Meets some constraints, ignores others | Meets all four constraints and shows the parts total | Meets all four constraints, shows the total, and explains what the team would cut first if the budget were smaller |
| Communication to the client | Disorganized; the recommendation is hard to find | Recommendation present but buried in detail | Clear summary page, readable table and graph, appropriate tone for a district director | Summary page stands alone, visuals are labeled and self-explaining, and the presentation answers questions directly |
Differentiation
Support
Assign these students the fixture inventory and the timing work, which is concrete and produces immediate data, and give them a partly completed data sheet with the columns labeled and the first row filled in. Provide a conversion card showing how to turn seconds per gallon into gallons per minute. Reduce the written proposal to the summary page and the results page, with the appendix collected as raw sheets.
Extension
Ask these students to estimate the annual cost of the standing use they measured, using the school district's actual water rate if the business office will share it, and to calculate a simple payback period for the parts they recommend. They can also design a second test that would separate leaking toilets from dripping faucets more cleanly than the first one did.
ELL supports
Pre-teach "meter," "reading," "standing use," "flapper valve," and "aerator" at the fixtures themselves during Session 1, pointing to each part. Provide a bilingual data sheet with picture labels for each fixture type, and give the proposal a paragraph-by-paragraph outline with sentence frames such as "Our team measured ___ gallons per hour overnight before the change and ___ gallons per hour after."
Extensions
Invite the fictional client's real counterpart, the district facilities director or a custodian, to hear the presentations and respond to the recommendations. Teams that measured a clear reduction can prepare a one-page summary for the school newsletter that explains what was changed and what the meter showed, using their own graph rather than a stock image.