Which of the following is not considered grey water?

Grey water is defined as wastewater that is generated from household activities, excluding water from toilets. This type of water typically comes from sources like sinks, showers, bathtubs, and washing machines. Each source contributes to what is classified as grey water, making it suitable for recycling under specific conditions.

In contrast, sink water, as the answer suggests, is considered grey water. It includes water used for handwashing, dishwashing, or other sink-related tasks. The distinction is important as grey water contains fewer pathogens compared to black water (which comes from toilets) and can often be reused for irrigation or other non-potable uses.

Shower water, bath water, and washing machine water are all examples of grey water. They fall under the category of water that can be repurposed for various applications, contributing to water conservation efforts. Therefore, sink water is indeed classified as grey water, making this answer inappropriate in identifying the source that does not belong to this category. Instead, the question may have been structured to look for a source that is less commonly related to grey water; however, based on the definitions and typical classifications in environmental science and waste management, sink water does qualify as grey water.