What is not a component of gray water?

Gray water refers to the relatively clean waste water that is generated from domestic activities such as bathing, washing dishes, and laundry. This type of water excludes any waste that has come into contact with human excreta, which is classified as black water due to its higher potential for contamination and the need for more intensive treatment. Therefore, the correct choice identifies the type of water not included in the gray water category.

Water from sinks, showers, and laundry all contribute to gray water as they are generated from typical household activities that do not involve human waste. Their lower contamination levels allow for various reuse opportunities, such as irrigation or flushing toilets, without the same level of treatment required for black water.