Reverse Osmosis

Reverse Osmosis (RO) seems to be a very popular filtration system used by home-owners.

It is said to be the 'finest means of filtration available today'.

This view is not universally shared - as will be discussed in a little while.

How does an RO System Work?

Water is forced under pressure through a semi-permeable membrane....which means the pores on the membrane are very small so as to allow 'only pure water' to pass through.

Impurities suspended in the water are rejected. Unfortunately, not all impurities can be stopped. (see microorganisms below).

I've got a Well - 
Is RO a good filter choice for me?

Absolutely - Yes

RO is an excellent choice where well water or lake/river/rainwater are your available water source choices.

Be also aware of impurities you cannot see. 

(see microorganisms below)

A cautionary note about microorganisms: 
What cannot be filtered by RO, alone.

Bacteria and viruses are examples of microorganisms. These, if present in the source water, cannot be rejected by Reverse Osmosis.

While the 'pure water' indeed passed through the did any microorganisms as they are much smaller.

Recommendation: Have your source water tested before you decide on which water filtration &/or purification Systems to use.

Your System selection must be tailored to deal with the specific challenges (if any) of your water.

We found Iron in our water - What to do now?

What is the first hint that iron is contaminating your source water?

The water is brown in colour. It does a magnificent job of leaving terrible brownish stains on sinks, toilet bowls etc.


You will need to pre-filter the source water before it reaches your water filtration (RO, in this case) system.

There are 2 ways to deal with the iron: Install a

  • water softener or
  • whole-house iron filter. It is important that the device chosen is installed upstream of your RO or other filtration unit. Otherwise, you can look forward to unnecessary additional expense from premature clogging , wear and tear on the membranes etc. (Typically the RO membranes, maintained as directed, have a 2 - 3 year lifespan.)
  • Microorganisms, harmful bacteria and viruses

    OK: So you have now determined that your source water is safe to drink, or if not, what filtration system is best for you.

    Are you out of the woods yet? Not necessarily. Danger can still be lurking.


    1. Water that has already been treated by the RO System usually is stored in a holding tank. Did you know bacteria and other nasties can fester in the pipes between the tank and the tap.
    2. Or perhaps you have a great NSF-certified filter in the cellar that cleans every drop of incoming water. Consider the pipes between that filter and your tap. If there is any distance involved, the idle water can become a breeding ground for nasties.

    Sidenote: there is an excellent way to take care of this scenario. Please use one of the forms located on this website if you want to know how. As it is not R.O., we won't deal with it here.)

    Are All Reverse Osmosis Systems the Same?

    What a good question!

    The short answer is: "No they are not."

    Like any other mechanical item, it is only as effective as the quality of the components, the engineering and the workmanship allow.

    Check the membrane and the pre-filters (quantity and quality).

    Low quality filters break-down prematurely. The RO system will suffer from membrane fouling, reduced performance, and purified water output and membrane life. This gets expensive.

    How Can I Judge Cost/Benefit of an RO System?

    This is a really great question! It's actually a 2-in-1 question.

    First, am I being overcharged? - because let's understand, RO systems are relatively more expensive than most other available systems.

    If you have done your research and for whatever reasons you decide that an RO system will meet your specific needs - go for it!

    Do some comparison shopping to determine value you will be receiving. Initial outlay is one thing, but sometimes it is better to pay a little more so you are assured of top quality after-sales service etc.  

    What is the Cost / Gallon of Water?

    As stated above, with the exception of the possible need for a water softener or pre-filter, are there other systems available that:

  • do not require so much physical space,
  • produce cool fresh, instead of, warm water,
  • more effectively deal with microorganisms,
  • are more efficient: Don't you think using up to 9 gallons of water to produce 1 gallon of drinking water by RO terribly wasteful?
  • do not require the major hassle of changing membrane filters.
  • (This is a terrible task.)

    We see RO systems more applicable to the Pulp and Paper industry rather than in sub-urban residential homes.

    Even for rural areas, you may be able to research more effective systems for less over-all cost. This is simply to make you aware so you can arrive at the best decision....for you.

    Improved Membranes for Desalination Processes

    Here is a great new development that will simplify the Reverse Osmosis least for desalination applications:

    New Development

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