What Does a Top-Quality
Reverse Osmosis System Remove from Tap Water?


Virtually anything you would want removed.

A reverse osmosis (RO) unit, depending on the style, contains one, two or more activated carbon filters. On the EPA's list of regulated contaminants, filter carbon is the recommended best treatment for the vast majority. For the removal of organic chemicals, chlorine and its by-products, pesticides, and herbicides, activated carbon is unrivaled. It is also unrivaled as a taste and odor improver. That's why Pure Water Products reverse osmosis units use the best carbon filters we can buy—in every case. Incredibly, a single MatriKX CTO+ cartridge (standard in most of our Black and White models) can remove the chlorine from 20,000 gallons of tap water!

In addition to its carbon filters, the reverse osmosis system sends the water through an extremely tight membrane that does some things carbon filtration alone cannot do. The accompanying “Nominal Rejection Characteristics” sheets show the typical rejection (removal) percentages of various water constituents. If there's lead in your water, for example, a typical thin-film membrane will remove 94% to 96% of it. If your water has a high amount of sodium, the same thin-film membrane will remove 90% to 95% of it. Sodium is not removed by normal filtration. In addition to the ions listed, other EPA-regulated contaminants that RO is a preferred treatment for include arsenic, asbestos, and all of the cancer-causing “radionuclides.” Also, the reverse osmosis membrane in conjunction with the carbon filtration that accompanies it is is the best technology available for the removal of chloramines, which many city water systems now use instead of chlorine. Reverse osmosis plus carbon is also the first choice for removal of the gasoline additive MTBE that's becoming more prevalent in our water supplies.

Concerned about cysts like giardia and cryptosporidium that have been in the news so much lately? The reverse osmosis membrane operates down to an unimaginably tiny pore size of 0.0001 microns. That's about one ten thousandth as big as even a very tight carbon block filter, which is itself much too tight for a giardia or cryptosporidium cyst to pass through. As for bacteria and viruses, the smallest virus is about ten times as big as the largest possible pore in an RO membrane. And by comparison, bacteria are giants. (Note: This should not be understood to mean that you should treat bacteria-contaminated water with an RO unit. That isn't its purpose, and the O-ring seals in reverse osmosis units are not designed to prevent the migration of bacteria.)

RO provides a full-range treatment that assures safe, great-tasting water at a very reasonable price. It's a proven performer that with minimal upkeep will provide a lifetime supply of pure and delicious drinking water. It's our choice as the best all-around drinking water provider.

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