Which of the following is an example of a non-potable water source?

Gray water is an example of a non-potable water source. It refers to water that has been used for tasks such as bathing, laundry, and dishwashing, and does not contain high levels of contaminants. While it is not safe for drinking due to potential pathogens and chemicals, gray water can be reused for certain applications like irrigation or flushing toilets, making it a valuable resource in water conservation practices.

In contrast, tap water is typically treated and safe for drinking, making it a potable source. Bottled water is also considered potable, as it is sourced and packaged for consumption. Distilled water undergoes a purification process that removes impurities, rendering it safe for drinking as well. Therefore, gray water stands out as a non-potable water source due to its prior use and the necessity for treatment before it can be repurposed.