Abstract: A water treatment system and related components for reducing contaminants in normal drinking water are provided. An enlongated tube has first and second ends and is connected with an interference fit at its first end to the interior surface of a neck of a conventional bottle. Water treatment media is disposed within the tube adjacent its second end, such as activated charcoal, silver impregnated media, ion exchange resins, or calcium and/or magnesium leaching material. The tube includes a flange adjacent its first end which minimizes the possibility that water will enter the bottle except by flowing through the open first end of the tube.