Reverse Osmosis Water Filters Buyer's Guide
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  We review, analyze and compare the best water filters in the industry including reverse osmosis systems, faucet filters, water distillers, pitcher filters, whole house filters, water softeners, shower filters, bottled waters and more.
 

Reverse Osmosis Filtration

 

A reverse osmosis water purifier protects you from the harmful effects of lead, heavy metals, chlorine, chemical contaminants, pesticides, pathogens, bacteria, viruses, and even radioactive materials.

micron comparison

RO is the most convenient and effective method of water filtration. It filters water by squeezing water through a semi-permeable membrane, which is rated at 0.0001 micron (equals to 0.00000004 inch!). This is the technology used to make (only the purest, but not all) bottled water, it is also the only technology capable of desalinating sea water, making it into drinking water Non-RO water filters are much less effective, and the pore size on these filter media are much bigger, generally 0.5 - 10 micron. They can filter out coarse particles, sediments and elements only up to their micron rating. Very fine particles and most dissolved substances cannot be filtered out. As a result, water is far less clean and safe compared to reverse osmosis filtration. 

What contaminants does an RO system remove? 

SEE RO CONTAMINANT REMOVAL CHART BELOW

What is Reverse Osmosis?

Reverse Osmosis, also known as Ultra-Filtration by the industry, represents state-of-the-art in water treatment technology. Reverse Osmosis (RO) was developed in the late 1950's under U.S. Government funding, as a method of desalinating sea water. Today, reverse osmosis has earned its name as the most convenient and thorough method to filter water. It is used by most water bottling plants, and by many industries that require ultra-refined water in manufacturing. Now this advanced technology is available to homes and offices for drinking water filtration.

 

How It Works

In short, it is the process by which water molecules are forced through a 0.0001 micron semi-permeable membrane by water pressure. Long sheets of the membrane are ingeniously pressed together and rolled up around a hollow central tube in a spiral fashion. This rolled-up configuration is commonly referred to as a spiral wound membrane or module. They are available in different sizes for processing different quantities of water. Typically, a module for home water treatment is as small as 2" diameter and 10" long, while one for industrial use may be 4" diameter and 40" long.

For the membrane to be usable, it must be in some type of container (membrane housing) so pressure can be maintained on its surface. It is this pressure that supplies the energy to force the water through the membrane, separating it from unwanted substances. The most amazing aspect of RO is that the substances left behind are automatically diverted to a waste drain so they don't build up in the system as with conventional filtering devices. This is accomplished by using a part of the unprocessed water (feed water) to carry away the rejected substances to the drain, thus keeping the membrane clean. This is the reason to why RO membranes can last so long and perform like new with minimum maintenance even after years of operation.

Reverse Osmosis Contaminant Removal List:

Giardia cysts

100%

Criptosporidium cysts

100%

DDT

>99.9%

PCB

>99.9%

E.coli bacteria

>99.9%

Fecal bacteria

>99.9%

Lindane

>99.9%

Salmonella typhi

>99.9%

Vibrio choleriae

>99.9%

Shigella disinteriae

>99.9%

Serratia marcescenes

>99.9%

Toluane

>99.9%

Sodium Fluoride 

99%

Calcium Cloride

99%

Sodium Chloride NaCl 

99%

Sucrose

99%

Magnesium Cloride

99%

Nickel Sulfate NiSO4

>99.9%

Copper Sulfate CuSO4

>99.9%

Lactic Acid pH5

99%

Glucose

98%

Sodium Nitrate NaNO3 

97-99%

Chlorinated Pesticides

99.9%

Silica SiO2

98%

Sodium

95-99%

Nickel

95-99%

Chloride 

99.9%

Radioactivity

95-99%

Potassium

92-99%

Zinc

95-99%

Bicarbonate 

99%

Sulfate

95-99%

Calcium

95-99%

Strontium

95-99%

Nitrate 3

90-99%

Ferro cyanide

96-99%

Magnesium 

95-99%

Cadmium 

95-99%

Fluoride

90-95%

Arsenic +3

95-99%

Iron 

95-99%

Silver

95-99%

Silicate 

95-99%

Arsenic +5

95-99%

Aluminum

95-99%

Mercury

95-99%

Phosphate 

95-99%

Lead

95-99%

Ammonium

95-99%

Barium

95-99%

Chromate

95-99%

Copper

95-99%