Most of the time, systems treat the combined wastewater from all sources in a structure. Occasionally, the decision is made to split the system so one or more components treat one source of wastewater while another component treats other sources. This will require separate plumbing networks in the residence or other building.
Graywater is the wastewater captured from nonfood preparation sinks, showers, baths, spa baths, clothes washing machines and laundry tubs. Toilet wastes from the residence or other establishment have to be treated in some other system, or the residence has to have a privy. To prevent hooking up a flush
