What does greywater harvesting involve?

Greywater harvesting specifically involves the collection and reuse of wastewater generated from household activities such as bathing, handwashing, and laundry, primarily from sinks, showers, and washing machines. This process is designed to reduce the demand on freshwater sources and minimize wastewater discharge into the environment. Greywater can be treated and reused for non-potable applications such as irrigation, toilet flushing, and other uses that do not require potable water quality.

The other options do not align with the definition of greywater harvesting. Collecting rainwater for irrigation refers to rainwater harvesting, while reusing rainwater in toilets is also distinct from greywater harvesting since it pertains specifically to harvested rainwater rather than used water from household activities. Filtering wastewater for drinking is a process associated with potable water treatment, which is not the focus of greywater systems and involves a more complex level of treatment than what is done for greywater reuse.