Reverse osmosis is a pretty 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 fluoride, 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."
Click here for more Wikipedia information: http://en.wikipedia.org/wiki/Reverse_osmosis
This 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. This is not true. Even many well-intentioned authors repeat this because they have seen it so many times. A bit more research however, will show the inaccuracy of that statement.
There are many disadvantages to the use of reverse osmosis in the home. In this list we are specifically speaking about use in the kitchen, although the concepts apply for the whole house too.
Water Supply & Environment
- Reverse osmosis filters waste a great deal of water - perhaps 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
- Reverse osmosis filters are relatively slow to process water
- If you use more water than usual, you can get ahead of the water supply
- 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.”
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 can break the bond between
chlorine and ammonia (ie chloramine) allowing carbon to readily absorb both.)
- 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 are more involved (and therefore most costly) to install
- Understanding the shortcomings of reverse osmosis, providers are more and more frequently combining ro with other types of filtration and even with units to rebuild the water to drinking quality - making larger, more complex and more expensive units in order to achieve what is better done by classic filtration.
* 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 - because 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?