Yeah, the old don’t waste water becous some people in africa don’t have drinking water :).
So every city/town is build next to a water source (river/ocean/sea), the water gets treated and pumpt to your house. Used water gose to a facility that cleans and removes the waste from it and returns the water to the source.
Having 2 tipes of water (one potable/one non) would meam 2x infrastructure maintainance.
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