The invention relates to a water purification system comprising a filter for placement at an inlet of a water storage vessel; the filter including a filter material through which water passes to enter the water storage vessel; and a purifier configured for placement on the outside surface of the water storage vessel and including an inlet for receiving water through an opening in the water storage vessel; the purifier comprising a purification chamber holding a composition for water purification; water received from the storage vessel passing in a reverse flow through the purification chamber. The invention also relates to a method of water purification comprising a first stage of passing water through a filter placed at the inlet of a water storage vessel to remove particulate matter and to obtain filtered water, and a second stage of passing the filtered watered through a purifier connected to an outside surface of the water storage vessel and containing a composition for purification of water to obtain purified water, the flow of water through the purifier in a reverse flow.
