Abstract: Apparatus for purifying water comprising a fitting for installation in a water line to define a primary water flow path. A Venturi tube is mounted in the fitting and positioned in the primary water flow path. A secondary water flow path is established between the fitting at either end of the Venturi tube and the inlet of a tank connected to the fitting. The tank houses a container having an outlet communicating with the primary water flow path which contains a bed of elemental iodine crystals. The Venturi creates a pressure differential forcing a small portion of the water in the water line to flow through the bed of iodine crystals in the container and then be returned to the water line.