Kilnbrook's Purified Water Plan: Reuse for the Drinking Supply

Resolution: The Kilnbrook Water District should build a purification plant that treats the city's wastewater to drinking water standards and returns it to the city supply.

Kilnbrook is a fictional inland city of about 60,000 people. Its only source is Bevin Reservoir, filled by snowmelt and spring rain. After three dry years the reservoir sat at 38 percent of capacity in September, its lowest level on record in this scenario. The city has no ocean nearby and no second river to tap. The nearest large aquifer lies under farmland forty miles away, and the farmers there already pump it hard.

Kilnbrook's wastewater plant treats about 5 million gallons a day and releases the treated water into Bevin Creek below the city. The proposed project would send that water instead through membrane filters, reverse osmosis, and an ultraviolet step, then blend it back into the reservoir. Engineers call a design like this a multiple-barrier train, because each stage removes a different kind of contaminant. A fictional engineering study prepared for the city council estimates the plant would cost $46 million to build.

Roles. The affirmative team argues for building the plant. The negative team argues against it and must name at least one alternative the city should fund instead. Two students serve as the council panel and ask one question of each team after the opening cases. One student times each round and records which evidence each team actually cites.

Format. Round one is a four-minute opening case per team. Round two is three minutes of questions from the council panel to each team. Round three is a three-minute rebuttal per team, and the negative team speaks last.

Each point below names its source. Points marked as fictional describe this scenario only and must never be presented as documented fact.

Case for the purification plant

1. Large systems already do this. Orange County's Groundwater Replenishment System is the world's largest indirect potable reuse facility at 130 million gallons per day, which shows the treatment train works at a scale far above Kilnbrook's. Source: Orange County Water District.
2. The coastal option is closed to an inland city. The Carlsbad plant in California is the nation's largest desalination plant at about 50 million gallons per day, yet it sits on the ocean shore. Kilnbrook has no seawater to treat. Source: Carlsbad Desalination Plant and San Diego County Water Authority.
3. Reuse is the lower-energy path to a new supply for a city like this one. Seawater reverse osmosis uses roughly 11 to 15 kWh per 1,000 gallons (about 3 to 4 kWh per cubic meter), against about 1 to 2 kWh for conventional treatment and delivery. Piping desalinated water inland would add still more pumping energy. Source: industry engineering references.
4. The water already exists. The city produces treated wastewater every day and sends it downstream. Recycling it adds supply without a new dam, a new well field, or a purchase from another district. Source: the design described in this kit's background.
5. The design does not depend on one barrier. Membranes, reverse osmosis, and ultraviolet treatment each remove different contaminants, so a failure in one stage does not put untreated water into the reservoir. Source: standard multiple-barrier treatment practice.
6. A fictional public works director in Kilnbrook testified that the reservoir has come within one dry winter of mandatory rationing twice in five years. This is testimony from this scenario, not a documented statistic.

Case against the purification plant

1. The price lands on ratepayers who are already paying more. Combined US water and sewer bills rose about 24 percent from 2019 to 2024 and about 5.1 percent in 2025, outpacing inflation. A widely used rule of thumb, built by adding two EPA benchmarks, treats combined water and sewer costs above about 4.5 percent of household income as a high burden, and EPA's 2024 affordability assessment also used a lower line of 3 percent. Source: Bluefield Research rate surveys and EPA's 2024 Water Affordability Needs Assessment.
2. Cheaper savings have not been captured yet. Household leaks waste an average of nearly 9,400 gallons per year, and the average US household uses about 300 gallons of water per day. A leak repair and meter program buys water at a far lower cost per gallon than a new plant. Source: EPA WaterSense.
3. The rules for emerging contaminants are still moving. The limit for PFOA and PFOS is 4.0 parts per trillion each, with compliance due in April 2029. In May 2026 EPA proposed letting eligible systems apply for a two-year exemption, to April 2031, while keeping the same limits, and the proposal was not final as of September 2026. Designing a plant while parts of these rules are still being revised carries real risk. Source: EPA PFAS National Primary Drinking Water Regulation.
4. Skilled staff are hard to hire. About 10,000 openings for water and wastewater operators are projected each year, on average, from 2025 to 2035, all from replacing workers who retire or move to other jobs, and roughly one-third of the water workforce becomes retirement-eligible within the next decade. An advanced plant needs licensed operators the city may not be able to recruit. Source: BLS Occupational Outlook Handbook and EPA workforce materials.
5. Public support is not there yet. A fictional survey of Kilnbrook residents found that fewer than half would vote for the bond that funds the plant. A project this size fails without a bond, so the district would spend two years and lose. This is testimony from this scenario, not a documented statistic.
6. One plant is one point of failure. If the purification plant goes offline for repairs, the city returns to the same reservoir it has now, so the project reduces risk less than its supporters claim. Source: the design described in this kit's background.