Reverse Osmosis

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 recommend against reverse osmosis.

Water Supply & Environment

  • Reverse osmosis filters waste a great deal of water – frrequently 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 particularly effective on many synthetic chemicals like herbicides and pesticides
  • RO 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. 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.”

Click to read more of this WHO Report.


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, kdf breaks the bond between chlorine and ammonia (ie chloramine) allowing carbon to readily absorb both. FOAM ADVANTAGE kdf greatly increases the effectiveness. So when foam 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 as much chloramine as you want to.)

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
  • Other Issues

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.  Do you want this process to go on in your own body?

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

Click the Shop tab above to see water filters using classical filtration.