Q. DON'T PEOPLE NEED THE MINERALS PRESENT IN WATER?

Most of the minerals that we receive are from the foods we eat. Only a very small percentage comes from the water we drink. If you're concerned about minerals, it's better to take a vitamin supplement and drink pure water than to drink water full of contaminants.

Q. DON'T FILTERS NEED TO BE CHANGED FREQUENTLY TO PREVENT BACTERIAL GROWTH?

Bacteria is likely to grow in the pre-filters of an R.O. system. Although chlorinated water will minimize bacterial growth in the sediment pre-filter, since the carbon pre-filter removes chlorine, there will probably be some bacterial growth in the carbon pre-filter. However, as you can see from this chart, the R.O. membrane will remove bacteria from the water coming from the pre-filters:


Secondly, there is bacteria on our food, dishes, silverware, hands, and faces -- as well as the hands and faces of those we come into contact with -- but because of our immune system, most of it is harmless. We need only be concerned about harmful bacteria. The Water Quality Association's contention is that the common bacteria in filters, which is known as heterotrophic plate count (HPC) bacteria, pose little if any health risk.

Q. ARE THERE OTHER COMPONENTS OF AN R.O. SYSTEM THAT COULD SUPPORT BACTERIAL GROWTH?

The components which follow the R.O. membrane could support bacterial growth. These include the tank, the post-filter, the faucet, and the post-membrane tubing. However, keep in mind, that at this point there are few nutrients in the water on which the bacteria can grow. Secondly, our post-filter will screen out bacteria which is larger than five microns. Thirdly, as noted above, the Water Quality Association contends that the common bacteria in filters, which is known as heterotrophic plate count (HPC) bacteria, pose little if any health risk. Nevertheless, if you are concerned about bacteria, you might want to drain your tank once a week and sanitize it once a year, as we mention here. You could also let the water run for a few seconds before filling your glass in order to flush out the tubing, the post-filter, and the faucet.