Reverse osmosis is a effective way to separate many contaminants from the water you want to use. Membranes allow pure water through while holding back water with contaminants in it, like chlorine and heavy metals.

As Wikipedia says:  “Reverse osmosis (RO) is a filtration method that removes many types of large molecules and ions from solutions by applying pressure to the solution when it is on one side of a selective membrane.”

The problem with that as a solution to get healthy water is that contaminants don’t sort themselves out by size of molecule. Having a large molecule does not equate with ‘good.’ Having a small molecule does not equate with ‘bad.’

It is endlessly repeated on the internet that reverse osmosis is the only way to remove fluoride (and lots of other contaminants). This is pure and unequivocal bunk. Even many well-intentioned web site authors repeat this because they have seen it so many times. If someone tells you that RO is the ‘only way’ to do anything – then they are either badly misinformed or not being truthful. Just a tiny bit more research will show the inaccuracy of these sorts of statements. There are many disadvantages to the use of reverse osmosis in the home.  In the list below we are specifically speaking about use in the kitchen, although the concepts apply for the whole house too.

We are an independent family-owned and -run company that can sell whatever types of filters we choose.  We almost always recommend against reverse osmosis.

             Click this link to go to Whole House Water Filters that use classic filtration without these issues. 

             Click this link to go to Fluoride Kitchen Filters that use classic filtration without these issues. 

      Click the Shop tab above to see many filters that leave healthy water.


How effective is Reverse Osmosis?

Water Supply & Environment

  • Reverse osmosis filters waste a great deal of water – frequently 70%
  • The water wasted is sent back into our environment with a highly saturated level of contaminants!
    • Most people aware enough to want to filter their water don’t want to waste it or further add to the contamination of our environment
  • Reverse osmosis filters store water in a tank that you draw from
  • Reverse osmosis filters are relatively slow to process water
    • If you use more water than usual, you can get ahead of the water supply

Health Issues

  • Reverse osmosis removes nutritional minerals (trace elements like magnesium, potassium and calcium) that the body needs
  • Removing minerals drops the pH of your drinking water, which increases free radicals, shown to increase risk of cancer
    • So you should rebuild your water if you use RO
  • Because reverse osmosis removes trace elements from the water, when the water is in your body, it tries to replenish itself – by taking trace elements from you! (see footnote *)
  • It seems that many drugs, which we know are in the water, are not removed by reverse osmosis
  • Reverse osmosis is not very effective on many synthetic chemicals like herbicides and pesticides
  • Reverse Osmosis is ineffective at removing Arsenic 3 – the type of arsenic that has health risks
  • RO lets molecules and ions through, or not, based on size.  This is not the best basis to ‘sort’ on.
  • “Dissolved gases and materials that readily turn into gases also can easily pass through most reverse osmosis membranes,” according to the University of Nevada Cooperative Extension. For this reason, “many reverse osmosis units have an activated carbon unit to remove or reduce the concentration of most organic compounds.”

There is a report from the World Health Organization that says:  “Salts are leached from the body under the influence of drinking water with a low TDS (Total Dissolved Solids). Because adverse effects such as altered water-salt balance were observed not only in completely desalinated water but also in water with TDS between 50 and 75 mg/l, the team that prepared the 1980 WHO report recommended that the minimum TDS in drinking water should be 100 mg/l.

“Demineralized water that has not been re-mineralized , or low-mineral content water – in the light of the absence or substantial lack of essential minerals in it – is not considered ideal drinking water, and therefore, its regular consumption may not be providing adequate levels of some beneficial nutrients.”


The Water Quality Association reports that Chloramines are small, stable molecules with no net charge making them difficult to remove by distillation, reverse osmosis, and ion exchange resins.

However, chloramine can be very effectively filtered.  The right type of kdf combined with the best type of catalytic carbon remove chloramine.  FOAM ADVANTAGE kdf (as in the filters we sell) greatly increases the effectiveness. When patent-processed kdf is combined with the right kind of carbon, the result is extremely effective chloramine removal – up to 100% in tests.

Even the right kind of carbon alone won’t take out nearly as much chloramine as you want to. It needs to be combined with the Foam Advantage kdf.

Health Risks by Chloramine in Water

read more on Health risk of Fluoride in Water and how to filter Fluoride out of your water

Physical Issues

  • Reverse osmosis filters take up more space under your sink than is necessary
  • Reverse osmosis providers recommend that you periodically clean your system with chlorine
  • RO units, particularly those built up to address the shortfalls of RO, are more involved (and therefore most costly) to install
  • Many reverse osmosis systems also add other parts to make up for the deficiencies of R/O – leading to more complex and expensive systems.

Read more on Friends of water filer’s Lab Test results:-


To illustrate how reverse osmosis water takes minerals from your body:  You cannot use reverse osmosis in a whole house system if copper pipes follow. The water takes minerals from the pipes in order to replenish itself. In doing so, it breaks down the pipes.  A similar things happens in your body.  The water will try to replenish itself.

LEARN MORE about water filter types, including what we call classic filtration.

Hopefully your family is not dealing with the extreme situation addressed below.  But this is an indicator of the support to health from the filters we sell – even in the most difficult situations.

February 2016:  We received this message:  

As a Naturopathic Doctor and Certified GAPS Practitioner I see many clients with the worst of the worst health situations. They come to me because traditional medical methods do not work for them due to the synthetic nature. We support the body so the body can fix itself and see great recovery of all of them.

“We have found many discrepancies with Reverse Osmosis water, however, many clients with the most unhealthy systems come to me, specifically the children with FPIES (Food Protein-Induced Enterocolitis Syndrome – roughly stated they’re allergic to the protein in food). These clients thrive on Friends Of Water filter systems. We do not know why yet but I’m currently researching the cause. I have my speculations and patterns showing the reason but I need the proof so I can post it to my readers. I do know your system doesn’t change the molecular structure of water in a harmful manner while it removes the fluorine (in addition to other contaminants)- which is detrimental to their systems.

“My mentor, Dr. Natasha Campbell-McBride says the RO water clumps, changing the molecular structure so the body can no longer recognize it. It then strips the body of nutrients as the body has to battle the unnatural clumped water.”

Becky Plotner, ND, traditional naturopath, CGP, D.PSc

Rossville, GA 30741
visit her on Facebook at
Nourishing Plot

The big point here is that you shouldn’t wait to see if you get some disease or bad reaction to the contaminant we know are in the water.  Get a water filter that does what it should – effectively remove contaminants, and leave the healthy trace elements that the body needs.

Fluoride Water Filters

Fluoride Water Filters

Click the Shop tab above to see water filters using classical filtration.
Updated in October 2018

Also read 9 Frequent Incorrect Statements about Water Filters | Ten Tips While Selecting a Water Filter


Friends of Water is a family-owned and family-run business founded in January 2006. We work to save water, filter water and celebrate water.

  • In Business for 19 years
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