What should not be included in greywater?

Toilet waste should not be included in greywater because greywater refers specifically to used water that does not contain significant amounts of human waste. Greywater is typically generated from sources such as showers, sinks, and washing machines, where the water is relatively clean and safe for certain reuse applications, like irrigation or flushing toilets after proper treatment.

In contrast, toilet waste is classified as black water due to the presence of pathogens, bacteria, and substances that can pose health risks. Black water requires a more complex treatment process to make it safe for any reuse, and it must be handled according to strict regulations to prevent contamination of water supplies and ensure public health. Thus, including toilet waste with greywater would violate these health and safety standards.