Reverse Osmosis Systems are remarkable pieces of equipment. They do an amazing job of removing many troublesome well water contaminants. Arsenic, Uranium and Sodium are just of few health related contaminants these system are designed to treat for.

But before making the final decision to install either a point of use or whole house RO system, you’ll definitely want to make sure the water going into your new system is low in both minerals and Hardness. If not, you might be setting yourself up for a very rude awakening. 

How Reverse Osmosis Works

Reverse Osmosis systems are really very simple when you get right down to it. An reverse osmosis membraneRO system utilizes a membrane style filter to capture harmful contaminants that can be found in well water, such as Arsenic and Uranium.

Basically, well water is “pushed” through a high tech membrane using a home’s normal water pressure coming from its well pressure tank (the big “egg shaped” tank most likely found in your basement). Contaminants are captured within the membrane fibers leaving the treated water that comes out on the other side safe for drinking and cooking.

There is a lot more technical info we could say about these systems, but in a nutshell, that’s pretty much how reverse osmosis systems work.  And they do work well!

Reverse Osmosis Systems | Sometimes They Work a Little too Well!

Most filter membranes incorporated in point of use (under sink) type filters, like those found in reverse osmosis systems, are designed to last, on average 3-5 years before  they need to be replaced. This number of course depends on many factors such as system & manufacturer quality, daily household water usage volumes and most importantly levels of contaminants found in a given water supply to begin with.

Here’s the catch:

In order for these membranes to work properly and to last this amount of time, the water going into the systems has to be quite “clean.” What do I mean by clean? It means that the water coming into a reverse osmosis system needs to be relatively low in common well water contaminants such as Iron, Manganese and Hardness (Calcium & Magnesium).

What happens if the water coming into an RO system is too high in these mineralhard water contents? The RO membrane becomes clogged – literally. Instead of the membrane being able to capture the things it was designed to capture, it now has to use its filtration fibers to capture the things it was never meant to filter out in the first place.

Standard paper cartridge style filters and even most full sized self back washing style filters are really only designed to capture larger particles. The pores or “gaps” found on the membranes of cartridge filters or the jagged mineral utilized in backwash style filters is simply too large to capture small diameter contaminants like Arsenic or Uranium.

This is where RO systems come in.

Because the pores on an RO membrane are so tiny, they do an incredible job at capturing even the smallest of contaminants like those found on Arsenic and Uranium particles. They unfortunately also do a very good job at capturing the things you don’t want them to capture, such as minerals and hardness.

The end result is that not only is the lifespan of that RO membrane drastically reduced, but more importantly, there is a really good chance that the RO membrane itself is no longer able to capture the amount of unhealthy contaminants it was designed to capture in the first place. It literally ends up “competing” with the other elements in the water.

It’s a lot like unknowingly using a screw driver to pound in a nail – it’s just not the appropriate tool for the job at hand.

Making Sure Your Water is Clean

If you have already determined that your home may need a reverse osmosis system to remove unhealthy contaminants like Arsenic, Uranium or Sodium, there is a very good chance that you’ve also done a a complete set of water tests.

If you haven’t done so you’ll definitely want to have your water tested for many of the aforementioned “competing” mineral contaminants we talked about.

If you have yet to do so, I would strongly recommend taking this step. Otherwise you may simply end up hoping for the best when it comes to the performance and lifespan of your new (and possibly costly) system.

Our recommendations to our customers when it comes to reverse osmosis systems and maximum levels for the “usual suspects” of  competing contaminants are typically as follows.

Hardness (calcium & magnesium):  No more than 60 mg/L

Iron:  No more than .30 mg/L

Manganese: No more than .05 mg/L


Please keep in mind that these are the maximums we recommend. Lower is definitely better when it comes to these minerals. The lower the numbers, the longer your system is going to last and the better a job it will do when trying to remove the truly unhealthy contaminants from your water.

reverse osmosisLet’s face  it, for the vast majority of homeowners who purchase a reverse osmosis system, providing healthy water for their family is the number one goal.

Why not take the simple extra step of performing a proper water test to help insure your new system will perform as it is designed to.

Like any other piece of high-tech equipment, if you treat it right, take care of it and use it for what it’s meant for, it will thank you in spades by taking care of you (and your family) for a very long time.


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