Abstract: A water purification system for treating grey water from household appliances such as baths, showers, vanity basins and washing machine (11-15) has branch-off pipes (29-33) from the usual drain pipes (17-21) these branch-off pipes lead to a storage tank tank (35). The branched off water is filtered by a screen filter (51) then circulated by a pump (53) in series to a heater (55). The system also includes a sediment filter (57), a carbon filter (59), color filter (61), an ultraviolet radiation unit (63), and hence via a shut-off valve (71), to a storage tank (73). The purified grey water can be used for car-washing, and garden and lawn irrigation. The system can be retrofited to an existing home or installed in a new home.