Which of the following is NOT typically considered a component of a municipal water supply system?

• A. Source (surface water or groundwater)
• B. Intake
• C. Treatment Plant
• D. Residential Water Heaters

Answer: (D)

Understanding how a municipal water-supply system is built helps explain why residential water heaters aren’t considered part of it. The system includes the water source (surface water or groundwater), the intake that brings water into treatment facilities, and the treatment plant that makes the water safe and suitable for use. After treatment, the water is distributed to homes and businesses through a network. Residential water heaters, while they use water delivered by the system, are end‑use devices located inside buildings and are not part of the municipal infrastructure itself. So, the item that isn’t typically considered a component of the municipal water-supply system is the home water heater.