Debate kit Grades 10–11 Social Studies & Civics
The Direct Potable Reuse Debate: Recycled Water for Rioverde
A structured classroom debate on whether a drought-stressed city should purify wastewater into drinking water, with a two-sided evidence file built from real projects.
Objectives
- Construct arguments for and against direct potable reuse using evidence, not squeamishness.
- Evaluate a public policy in terms of costs, benefits, risk, and public trust.
- Practice formal debate conduct: timed speeches, rebuttal, and cross-examination.
Teacher overview
Direct potable reuse, which means treating wastewater to drinking standards and returning it to the distribution system, is a policy question on which honest experts hold a nuanced view: the technology works, and hesitation about adopting it is still reasonable. This balance makes it well suited to classroom debate. The science favors the affirmative, while the politics, the questions of public trust, and some of the economics give the negative genuine material, so neither team is left defending an empty position.
Some students may begin with an instinctive reaction against the idea. The evidence file is designed to move the discussion past that reaction. The strongest affirmative argument shows that every downstream city already drinks treated wastewater drawn from its river, so the question is really how long and how controlled the loop should be. The strongest negative argument concerns trust, cost, and the reliability of the institutions that would run the plant, rather than distaste. A debate that ends on the question of institutional competence has served its purpose.
The format below is a compact two-team structure that fits in two class periods. In the first session, teams receive the file, build their cases, and deliver constructive speeches. The second session holds rebuttals, cross-examination, closing statements, and a class vote with a written justification.
Resolution & Background
Resolved: The city of Rioverde should adopt direct potable reuse as its next source of drinking water.
Rioverde is a fictional city of 400,000 in a drought-prone region, assembled from real cases. Its river supply is over-allocated, and its aquifer is dropping. The council is weighing three options for the next twenty years. It can build a direct potable reuse plant, or a seawater desalination plant with the coast 60 miles away. The third option is to buy imported water at rising prices while pushing hard on conservation. The reuse plant is the cheapest of the three to operate and the most controversial to approve.
Teams must use two key terms accurately. Direct potable reuse sends purified water straight into the drinking system after treatment. Indirect potable reuse first rests that water in a groundwater basin or reservoir. The difference matters in the evidence and in how the public reacts.
Evidence File
Evidence both teams may use — Affirmative-leaning:
- Multi-barrier treatment produces purified recycled water. The barriers are microfiltration, reverse osmosis, and ultraviolet light with advanced oxidation. Each barrier on its own removes most contaminants. Stacking them means that when one barrier fails, the next one catches what it missed.
- The approach is proven at scale in its indirect form. Orange County, California has run its Groundwater Replenishment System for years at about 130 million gallons per day. It is the largest facility of its kind in the world, and its purified water has consistently met or bettered drinking water standards (figures as of mid-2026).
- El Paso, Texas already draws part of its supply from indirect reuse. It is now building the nation's first full-scale direct potable reuse facility of its kind, at roughly 10 million gallons per day. The city spent years on public engagement first, including plant tours and taste tests.
- Every city downstream of another city already practices unplanned reuse. The upstream city discharges treated wastewater to the river, and the next city draws it back in at its intake. Direct potable reuse shortens that loop and adds far more treatment, monitoring, and control than a river provides.
- Reuse is drought-proof. The supply arrives every day no matter how much it rains, and it grows along with the city that produces it.
- Reuse usually needs less energy than seawater desalination. Wastewater is far less salty than the ocean, so there is less salt to push out of it. Desalination runs roughly 11 to 15 kilowatt-hours per thousand gallons, against about 1 to 2 for conventional supplies, and reuse falls between the two.
Evidence both teams may use — Negative-leaning:
- Direct reuse removes the environmental buffer. In indirect reuse, water rests in an aquifer or reservoir for months. That delay leaves time to catch a treatment failure before anyone drinks the water. Direct reuse cuts that safety margin to hours. That is why regulators require extensive real-time monitoring, and why some states took years to write rules for it.
- The technology is unforgiving of institutional weakness. The multi-barrier design assumes disciplined operations, constant monitoring, and fast response. Yet roughly a third of the water workforce is nearing retirement, and a treatment plant's reliability depends on its staff.
- Losing public trust carries a lasting cost. Some cities rushed reuse without engaging residents first, and their projects were canceled after a public backlash. That wasted the planning money and soured the next attempt. A city that cannot convince its residents may end up paying for the plant and the imported water.
- Reverse osmosis leaves behind a concentrated brine stream, and the city has to dispose of it. Inland cities like Rioverde have no ocean outfall, and handling that brine can add real cost and environmental harm.
- Conservation is cheaper than any new supply. A dollar spent on fixtures, leak repair, and lawn conversion usually saves water for less than it costs to make new water. The fair question is whether Rioverde has used up the cheap option before buying the expensive one.
- Rate impact: reuse plants cost a great deal to build, and those costs land on water bills. Many low-income households already struggle to pay, and combined water and sewer bills have been rising faster than inflation nationally.
Debate format:
- Affirmative constructive (5 min) — 2. Negative constructive (5 min) — 3. Cross-examination, each direction (3 min each) — 4. Prep time (5 min) — 5. Negative rebuttal (4 min) — 6. Affirmative rebuttal (4 min) — 7. Closing statements (2 min each) — 8. Class vote with a one-paragraph written justification citing at least two pieces of evidence.
From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.
Rubric
| Criterion | 4 — Exceeds | 3 — Meets | 2 — Approaching | 1 — Beginning |
|---|---|---|---|---|
| Use of evidence | Accurately deploys multiple file items and explains their significance; distinguishes direct from indirect reuse correctly | Uses at least two file items accurately | Evidence used loosely or with accuracy slips | Assertion without evidence |
| Argument quality | Anticipates the other side's best case and answers it | Clear reasons connected to the resolution | Reasons present but underdeveloped | Restates position without reasons |
| Engagement with opposition | Cross-examination probes real weaknesses; rebuttal responds to what was actually said | Responds to major opposing points | Rebuttal mostly repeats the constructive | Ignores the opposing case |
| Conduct & delivery | Timed, organized, persuasive; respectful under pressure | Within time; organized; respectful | Some disorganization or time trouble | Unprepared or disrespectful |
Judging note for the teacher: the vote justifications are the assessment artifact for non-speaking students. Full credit requires citing evidence from both sides, and a justification that only repeats the winning team's case earns a 3 at most.
Differentiation
Support (below grade level)
Assign the evidence file with the bullets pre-sorted and highlighted, and give speaking students a speech skeleton (claim, evidence one, evidence two, "our opponents will say... but..."). Allow the constructive speech to be delivered from notes as a pair.
Extension (above grade level)
Remove the pre-sorted labels and hand the evidence as one unsorted list, so that deciding which side each item serves becomes part of the analysis. Add a third negotiating role: a council member who must draft the conditions under which they would vote yes (monitoring requirements, rate protections, an independent review board), turning the binary debate into policy design.
ELL supports
Pre-teach reuse, wastewater, barrier, buffer, and brine with a diagram of the treatment train. Provide the debate format as a visual timeline. Allow the written vote justification in the student's strongest language with an English summary sentence.
Extensions
After the debate, show students where their own city's wastewater goes and where its drinking water comes from, including whether its intake sits downstream of another community's discharge. If your utility has considered reuse, its planning documents are public records; reading the actual staff report to council closes the loop between the classroom exercise and the real decision it imitates.