Which of the following is NOT a typical use for collected rainwater?

• A. Non-potable uses like irrigation
• B. Toilet flushing
• C. Drinking water without treatment
• D. Landscape irrigation

Answer: (C)

Rainwater harvesting is aimed at reducing the use of treated municipal water by supplying water for non-potable needs. Collected rainwater is commonly used for non-potable purposes such as irrigation and landscape watering, and for toilet flushing, because these uses don’t require water to meet drinking-water standards and they can be managed with basic filtration and treatment measures.

Drinking water without treatment is not a typical use because roof runoff and catchment systems can pick up contaminants—bacteria, parasites, chemicals, metals, and debris. To be used as drinking water, rainwater must undergo substantial treatment (filtration, disinfection, ongoing testing) and meet drinking-water quality regulations. Without that treatment, it poses health risks, so it’s not considered a typical use for collected rainwater.