a water purification apparatus comprising a semi - permeable membrane capable of being contacted with a water source ; a superabsorbent polymer capable of absorbing water across said semi - permeable membrane ; a pressure application surface capable of transmitting pressure to the gel ; and a permeable membrane through which absorbed water is capable of being released from the gel upon application of pressure thereto from said pressure application surface , wherein said permeable membrane is isolated in use from the water source by an isolation means