The average American uses 80 -100 gallons of water per day. Less than half is used for cooking or drinking, all of it is most likely treated, potable water from the local municipality.
Potable Water: water that is safe to drink or to use for food preparation, without risk of health problems.
Alternatively, water can be ‘harvested’ or ‘caught’ from the sky and gathered or stored in cisterns. This ‘catch water’ is then filtered to make ready for human consumption and use through filters.
The cisterns can be buried, preferably above ground or integrated into the interior of the building and used as a heat sink and optionally have a small waterfall incorporated.
The Cistern(s) can be ‘inter-tied’ to connect to municipal water so that when the water gets low, to a prescribed level, more water can be automatically added.