Reviews and General Information
for Improving the Quality of Water

Reverse Osmosis Water Filtration – How It Works

This informational page on my website is possibly one of the most difficult I’ve had to put together. After all, I’m an average member of the public just like you. The only difference with me is that during my quest for crystal clear and tasty water in my home I took a (what some might say unhealthy) interest in how water filtration works, especially reverse osmosis.




Plus, during my quest I have found that a good many manufacturers appear to expect the average person to understand all the “ins and outs” pertaining to the technology they use. Reverse osmosis (or RO) is a very popular form of water filtration and that’s why I believe it deserves a special mention.

So, how does it work? You may be thinking that I’m about to go all scientific on you, and I could but that’s not what I’m about. Instead, I want to make it as simple as possible for you to understand so you can decide if this type of filter will work for you.

A Bit Of History First

I’ve decided to add a few words on this subject simply because I was asked the question when reverse osmosis all started. Originally it was developed as a way of separating seawater from salt, and in our ever growing global population, RO is possibly one of the best inventions we have right now.

Some time after, when bottled water became popular, companies adopted this technology to protect the precious liquid inside the bottles from various contaminants.

On to How Reverse Osmosis Works

Reverse Osmosis

As said, I’m not going to baffle you with science but what I will say is the heart of any RO water filter is the semi-permeable membrane. The term reverse osmosis means pressure is used to force water through the membrane so all those nasty contaminants cannot follow.

There is a plethora of information out there dealing with what these membranes are made of, but for the most part you will come across the abbreviation TFC on my website. If you want to know more about this, take a look at my section technicalities and abbreviations.

Most of the water filters I have reviewed here give the “heart” of the system a little added help. For instance the Watts Premier RO-Pure 531411 and the iSpring 75GPD 5-Stage Water Filter are (in my humble opinion) two of the best reverse osmosis filtration systems on the market right now.

Reverse Osmosis System

As water enters the filter, it’s first put through a pre-filter which traps larger particles such as silt and sediment. After that, pressurized water is sent through the RO membrane which will filter out all of the contaminants and impurities you would rather not have in your drinking water. Once this has all happened, you water will receive a final “scrub” so it’s ready to drink.

Incidentally, the very best (and I have to say most expensive) filters of this type will deal with impurities as small as .001 microns in size.




So, there you have it, a very simple explanation of how reverse osmosis works. The fact is that even without all the science being explained, if you have a water filter that works in this way you’ll end up with crystal clear water that doesn’t smell or contain any potentially harmful contaminants. And that’s what counts.

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