How Reverse Osmosis Works

RO Filter Diagram Cutaway

The Process

The reverse osmosis process is a filtration method in which water is passed through a filter membrane with pores so small that only pure water is able to get through. Other contaminants are physically too large to pass through the membrane, so they do not enter the water supply.

Reverse Osmosis removes the widest spectrum of contaminants of any water treatment process. Water is forced through semi-permeable membranes leaving the dissolved particles in the more highly concentrated solution.

Bottled Water Vs Reverse Osmosis Systems

An emerging concern with bottled water has been the recently discovered presence of microplastics. A study conducted at the State University of New York in Fredonia tested 259 bottles of water from 11 brands across 9 countries. Out of the 259 bottles tested, only 17 were found to be free of plastic. In fact, on average, each liter sold contained 325 pieces of microplastic. These contaminants included polypropylene, nylon, and polyethylene terephthalate. A publication from the World Health Organization recommends the use of Reverse Osmosis Systems to remove microplastics from drinking water.

Annual Price of Reverse Osmosis Vs Bottled Water

The National Academies of Sciences, Engineering and Medicine recommends that men consume about 125 ounces of fluid a day and women should drink about 91 ounces daily. You get around 20% of this from food. If we use this model and assume you buy bottled water in bulk from Costco the price would be around 70 cents per 16.9 ounces which breaks down to 4 cents per ounce.

If you follow the recommendation and drink 100 ounces per day you can calculate your cost like this:

  • Men: 4 cents per ounce x 100 ounces daily = $4.00 per day. That's $1,460 annually.
  • Women: 4 cents per ounce x 73 ounces daily = $2.92 per day. That's $1,065.80 annually.
pouring bottled water into a glass

Let's compare this cost to the yearly cost of the All American Reverse Osmosis System. The 5-stage AARO ( All American Reverse Osmosis System) starts out at $349.95, the filters for this system need to be changed annually or semi-annually depending on water conditions. Let's assume you need to purchase filters every six months. The price of replacement filters runs $59.95 but you can save 10% if you enroll in autoship. The annual cost breaks down like this:

Initial purchase price ($349.95) + replacement filter cost if replaced every 6 months ( $59.95x2) = $469.85 for the first year and $119.90 annually.

The annual cost of purchasing bottled water is over 10 times the cost of Reverse Osmosis.

Typical Contaminants Removed By Reverse Osmosis

Contaminant Reduction Contaminant Reduction
Algae 99.90% Mercury 98.00%
Aluminum 98.00% Mold 99.90%
Amoebic Cysts 99.00% Nickel 95.00%
Arsenic 95.00% Nitrate 89.00%
Asbestos 99.00% Phosphate 95.00%
Atrazine 95.00% Potassium 95.00%
Bacteria 95.00% Protozoa 99.00%
Barium 97.00% Radioactivity 95.00%
Calcium 99.50% Sediment 99.00%
Chloride 95.00% Selenium 95.00%
Chlorine 99.90% Silicate 89.00%
Chromate 94.50% Silver 97.00%
Copper 99.00% Sodium 94.00%
Cryptosporidium Cysts 97.00% Strontium 97.00%
Cyanide 97.00% Sulfate 95.00%
Fluoride 98.00% Thiosulfate 99.00%
Giardia Lamblia Cysts 99.00% Trihalomethane 98.00%
Lead 97.00% Volatile Organics 95.00%
Manganese 98.00% Zinc 97.00%
Magnesium 97.00% Z, 4-D 95.00%

How To Install A Reverse Osmosis System

Every Reverse Osmosis System sold by US Water Systems comes with an easy to read installation guide. If that's not enough, then we also have step by step installation videos available for every product we make. While the installations are simple and straight forward, you can also hire a plumber to perform the installation.

A Commitment To Transparency

As a general rule we suggest that our customers purchase one of our water tests before buying a system. The test is sent off to an independent 3rd party laboratory for testing. This allows us to provide independent and unbiased facts to our customers regarding the underlying cause of their current water issues. More importantly, it allows us to provide different solutions to the water issues that our customers face. Even better, if you choose to go with one of our recommended systems, the water test acts as a $100 credit towards the purchase price.