People with high blood pressure or heart disease should consult their physician before consuming water from softeners that contain exchanged sodium ions. If ion exchangers have been designed to remove non-hardness chemical ions such as nitrate, the resins used can only be recharged at special facilities, making this form of treatment much more expensive. Reverse Osmosis is a membrane separation process that uses a very thin membrane that strains undesirable elements from running water. RO membranes can remove most major types of contaminants, but there are some organic chemicals that may not be efficiently removed. An RO system works by forcing high-pressure source water through the filter membrane.
Pure water collects on one side of the membrane, while pollutants accumulate on the other.
The pollutants are then periodically discharged by flushing them to the septic or sewer system. Most RO membranes will last for at least one year before they need to be replaced. These systems are normally POU, because they treat most effectively small volumes of water. You should do your homework carefully, and ask for references, to determine the proper system for your treatment requirements and to insure yourself against being sold a system that does not work or is more elaborate than you need. Remember, your service provider is required by law to inform you if your system's water has exceeded any of the maximum contaminant levels established by the Safe Drinking Water Act.