Cardwell County's Cistern Ordinance: A Grade 10 Debate Kit

Resolution. Resolved: Cardwell County should require every new single-family home to include a rainwater cistern plumbed for outdoor use.

Background. Cardwell County is fictional, and so are its officials, its builders, and its water district. The national figures cited in the evidence file are real and are labeled with their sources.

The county sits at the edge of a growing metropolitan area. About nine hundred new houses have been built there in each of the last four years. All of them connect to the county water district, which draws from three wells and one small treatment plant.

Two problems arrive together each summer. The district's peak day, which falls in July, runs close to twice its winter average, and lawn watering is the main reason. Meanwhile, the new subdivisions have replaced fields with roofs, driveways, and streets, and the creek that receives their runoff now rises faster after storms than it did ten years ago. Two road crossings have washed out since the last comprehensive plan.

The proposed ordinance would require a cistern of at least 300 gallons on every new single-family house, connected to the roof gutters and plumbed to an outdoor spigot only. It would not apply to existing homes, to apartments, or to commercial buildings. Inspection would be handled at the existing final building inspection.

Roles. Divide the class into an affirmative team and a negative team, with one moderator and two judges drawn from either side or from students who prefer not to speak. The affirmative supports the ordinance and speaks first and last. The negative opposes it. Each team files a one-page written case before the round, and each speaker keeps flow notes on index cards.

Format. Affirmative constructive, six minutes. Negative constructive, six minutes. Preparation break, three minutes. Negative rebuttal, four minutes. Affirmative rebuttal, four minutes. Cross-examination of two minutes follows each constructive, with questions asked by a speaker who does not deliver that side's rebuttal. Judges score with the rubric and give one sentence of oral feedback per criterion.

A rule for both teams. Any evidence point you use must be identified as a documented figure with its source, as an estimate from a person in the scenario, or as reasoning drawn from the background. Judges deduct for treating a stakeholder's estimate as a documented fact.

Points marked as documented rest on published national sources or on standard engineering references, identified in the point. Points marked as scenario evidence come from people inside this fictional county and are opinions or estimates rather than established facts. One point is marked as reasoning from the scenario, which draws a conclusion from facts already stated in the background rather than reporting a new figure.

Case for the ordinance

1. Documented. EPA WaterSense reports that the average US household uses about 300 gallons of water per day, with roughly 70 percent of that used indoors. The remaining outdoor share is the part a cistern can serve, and it is the part that swells in summer.
2. Documented. A standard rainfall conversion used by engineers is roof area in square feet multiplied by rainfall in inches multiplied by 0.623, which gives the gallons of rain that fall on the roof, although a real collection system captures somewhat less than that. A roof of 1,600 square feet therefore sheds about 997 gallons in a single inch of rain, which is more than three times the proposed cistern size.
3. Documented. Standard stormwater design values put the runoff coefficient of pavement near 0.9 and of lawn near 0.2, meaning pavement sends most of the rain that falls on it downstream while lawn sends only a small share. Replacing fields with roofs and driveways raises the peak flow the creek receives, and capturing part of the roof share reduces it.
4. Scenario evidence. The county water district's engineer estimates that meeting the projected summer peak with new supply would require a fourth well and an expansion of the treatment plant, and she describes the cost per household as several times the cost of the required cistern.
5. Scenario evidence. A builder who works in the county testified that installing a cistern during construction costs a fraction of what the same installation costs as a retrofit, because the gutters, grading, and spigot are already being placed.
6. Scenario evidence. The county's stormwater coordinator reports that both washed-out crossings failed during storms following new subdivision construction upstream, and argues that requiring capture at the source is cheaper than enlarging culverts later.

Case against the ordinance

1. Scenario evidence. The regional builders association estimates that the requirement adds cost to every new house in a county where the median buyer is already stretched, and it notes that the ordinance places the entire burden on people who have not moved in yet.
2. Reasoning from the scenario. Peak demand arrives in July, which is also when it rains least. A cistern that has been drawn down through a dry stretch is empty exactly when the district needs the relief, so the measure may reduce annual use without reducing the peak day that drives the need for new supply.
3. Scenario evidence. The county has one building inspector, and the county attorney's memo notes that the county has no written standard for cistern screening, overflow routing, or the separation between cistern plumbing and household plumbing. An unmaintained cistern can breed mosquitoes, and an improper connection can send untreated water into a house.
4. Documented. Because roughly 70 percent of household use is indoors according to EPA WaterSense, the largest share of demand is beyond what an outdoor-only cistern can touch. The Water Research Foundation's 2016 study of single-family homes found that toilets accounted for about 24 percent of indoor use, and the ordinance does nothing about that.
5. Documented. EPA WaterSense reports that household leaks waste an average of about 180 gallons per week, close to 9,400 gallons per year. A leak detection and repair rebate reaches every house in the county rather than only the newest ones, so the negative can argue that the same effort buys more water saved.
6. Scenario evidence. The district's operations manager says that the nine hundred houses built each year are a small fraction of the county's housing stock, so even full compliance changes the system slowly, while the creek crossings need attention now.