Reverse Osmosis water purification – what is it and why do I use it?

What is Reverse Osmosis?

Let’s start with the simplest explanation of Reverse Osmosis. You are all familiar with window screens which let air pass through and keep bugs out. Reverse Osmosis systems have permeable membranes which act like window screens, except that the holes are so small that they only let small molecules like water through and keep larger molecules like crud, arsenic, and other water system contaminants out. The result is that you can take your average municipal or well water and easily make it healthy and delicious to drink.

Since the holes in the permeable membrane are microscopic, it takes 45-60 pounds of pressure and a lot of square feet of membrane in order to filter enough water to drink. Additional stages of pre-filters and post-filters are added to increase the efficiency of the filtering process.

There are many available combinations, but I prefer a system with many stages of filtering and a high intensity UV radiation stage to kill off bacteria.

Water is necessary for life. The other contaminants are not, no matter how many experts with a hidden agenda claim that water needs vital minerals to make you healthy. You can get all of the vital minerals you want by drinking out of a dirty glass or more acceptably, by eating fresh and natural foods.

Why I choose to use an RO system

Municipal water systems are under increasing pressure to produce potable water out of increasingly polluted rivers and groundwater systems. In many areas, the water is unpleasant to drink because of the heavy chlorination required to kill bacteria in the water system. The increasing sales of bottled water are an indication of consumer reaction to the state of their drinking water.

Twenty years ago I experienced really pure water for the first time and it was a mind-blowing experience. This was glacier water from Canada with less than 4 ppm (parts per million) of total dissolved solids. It woke me up to the fact that total dissolved solids was an excellent indicator of water quality.

Dasani, an excellent bottled water from Coca-Cola, has only 15 ppm of total dissolved solids. Most other bottled waters do not list the TDS level (total dissolved solids), because the numbers would reveal that their TDS counts were the same as ordinary tap water (TDS=100-200 ppm). Mineral waters have TDS numbers in the 250 ppm range which is why they taste like they do.

My previous RO system produced water with a TDS level of 5 ppm (three times better than Dasani!) from a public water supply with TDS counts as high as 175 ppm. You could easily smell the difference between the public water and the filtered water. This was a major selling point when we listed that house for sale.

What kind of system configuration do I use

In the past, I had good results with a 6-Stage Reverse Osmosis (RO)/Ultra Violet (UV) System with 35 Gallon per day capacity. This time I ordered a similar system with 100 Gallon per day capacity to give me a faster recovery rate. A 100 GPD System generates 4.16 Gallons of filtered water per hour. This water is only used for cooking, drinking and ice-making so a 4.16 gallon/hour rate is entirely sufficient.

If you have not installed an RO system before, I would suggest a simple installation in a closet or under a kitchen counter. You can do the installation in a few hours if you are handy with tools. This will give you a cost-effective installation.

After you have used an RO system for a few years, you may find that you want the convenience of pure water taps at every sink in the house. Multiple taps increase the cost and complexity of the system significantly, because a demand pump is required to ensure that there is adequate pressure at taps remote from the RO system. In addition, there is the additional effort and expense of installing piping for all of the taps. However, like many conveniences that become necessities through use, pure water on demand is a keeper!

One suggestion, buy a TDS meter now and use it to check out your water supply and the various water "purifiers" that screw on a faucet or are built into your refrigerator. Test some Dasani as a reference and compare the taste of the water to the TDS figures. You may find out that you cannot taste any difference! If so, you may not realize one of the major benefits of an RO system.

RO system specifications

The supplier of my RO system is Pure Water Planet Inc, which manufactures the systems in Chatsworth, CA. The owner of the company is quite knowlegeable and was able to answer all of my questions and suggest a system onfiguration that would work best for me

The system I ordered is an AHS6-100UV 6-Stage Reverse Osmosis (RO)/Ultra Violet (UV) System with 100 Gallon per day capacity. Here are a brief description of the specifications for each stage:

1st Stage – NSF 5 micron 10" high-capacity polypropylene sediment filter –removes dust, particles, and rust.

2nd Stage – NSF Carbon Block 5 micron 10" –removes chlorine, odor, organic contaminants, pesticides, and cysts.

3rd Stage – 100 GPD TFC(Dow Chemical)  reverse osmosis membrane –reduces 93% to 98% of Total Dissolved Solids most chemicals,  metals, bacteria,  viruses and other contaminants. 

4th Stage – NSF GAC Inline Filter  – Reduces chemicals, chlorine, improves taste, odor and improved clarity.

5th Stage – 10" GAC Pre-Filter Cartridge for increased purification

6th Stage – UV Sterilization Light – The germicidal UV light kills bacteria and virus on contact with an efficiency of 99.9%. 


I have no interest in any RO company and am providing this information in the hopes that it will offer you some options for a healthier lifestyle.

As an interesting aside, our cats used to drink out of muddy puddles rather than drink water from our local water utility. Once they discovered the purified water that come out of the little taps at every sink, they insisted on drinking that water in preference to any other. I can put down two bowls of water, one tap water and one RO purified water, and the cats will choose the purified water every time.

Perhaps you should give yourself and your family the same opportunity.

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