Wastewater is liquid waste expelled from industrial or commercial processes, but does not include water uncontaminated by process waste or household sewage.
Wastewater from household functions such as washing dishes, laundry or bath water is called greywater, whilst wastewater contaminated by sewage is known as blackwater. there are numerous processes that can be used to clean up both types, such as various forms of reedbed systems.
See also: Sewage treatment, water resources