Abstract: A flushing water-circulation type flush system to purify living water or sewage into clean water. Water discharged from a toilet is directed successively to a filter bed unit having filter material therein, to an aeration unit, to a settling unit where solids are settled out, to a pH regulation unit containing an adsorber column having activated carbon therein, the pH unit also containing a source of calcium carbonate, with the adsorber extending therethrough. Outflow from the adsorber is passed through a sterilizer unit to a flushing water unit which serves as a source for supplying flushing water to a water reservoir for the toilet.