This house is not on main drainage, so the incoming water is already gauged by us as we know the limits of the cess pits (2, each of 1000 gallons) and they are only emptied once a year which averages under 6 gallons a day.  That is for 2 people.  As we are a rural and not an urban area, standpipes would be a considerable drain on the physical collection of water for pensioners.  Enhanced groundwater extraction is a contentious subject as that is the source of the springs for our rivers and hence our wildlife.  Desalination plants are possible, but local planning is a drawback unless waste water sites could be extended to include this.  No untreated waste should go to the sea anyway.