A lightweight, portable, water purification device can be used to recover potable water from any water source. The manually operated device, requires no external power, is very lightweight, and removes salt and other impurities from source water while also disinfecting it. A symmetrical reverse osmosis (RO) membrane coupled with a pre-filter is used to remove salt and impurities from the raw water. Metal biocides are integratable to disinfect the permeate, improve wet storage and to significantly reduce biofouling within the RO membrane.