A commercial building aims to reduce potable-water use by utilizing alternative water sources for appropriate...

Option C is the only choice that expressly requires treatment sufficient for the proposed potable applications. Graywater is normally directed to nonpotable uses, such as toilet flushing, irrigation, or cooling-tower makeup, because untreated graywater does not meet drinking-water standards. It may be used for potable purposes only when comprehensive treatment produces water that satisfies all applicable public-health regulations, testing requirements, and plumbing codes. Option A provides little meaningful potable-water reduction because alternative supplies are used only as backup. Option B appropriately assigns graywater to cooling-tower makeup but incorrectly directs harvested rainwater to drinking fountains without specifying potable-grade treatment. LEED v5 encourages the responsible and safe use of resources, so alternative water must be matched to an end use according to its quality and required treatment.

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