Actually, you are looking at the sole water source for the family. Water is channeled via pvc pipe from the roofs into the tanks where it is stored. There is a supply loop that is powered by an "on-demand" pump and a series of micron and UV filters back to the house (exactly like those used by a typical water well system). The pressure is provided by the pump. The bathroom lavatories and air conditioning condensate were connected to a separate drain line that collects water used for gardening.