Issue 1 - Maintenance
Reverse Osmosis systems require a lot of maintenance in order to retain high quality water output. There are many aspects of the R.O. system that mus be maintained, serviced and changed in order to retain high water purity. If not done, then membrane fouling and breakdown may occur. Another concern is that most of the systems have a holding tank that must be cleaned out regularly to prevent growth of bacteria.
Issue 2 - Fouling and Breakdown of Membranes
As described in Issue 1, R.O. machines require a lot of expensive maintenance, and if this is not scheduled properly then membranes may break down or begin to foul, resulting in water that smells so bad that it would keep people from drinking it. To solve this, new membranes have to be bought repeatedly adding to the operational costs, and the system needs to be cleaned to keep from fouling. Some manufacturers state that membranes last for several years, the fact is that they do not.
Issue 3 - Level of Water Purity
R.O. machines claim that they remove around 98-99% of all organic chemicals, whereas a simple carbon filter will do the exact same (and cost you much less). After a few months of operation, this percentage will fall to around 50-80%. Purity levels stated by manufacturers are rarely met in environments outside the laboratory, which means that when put to work the water will not meet the specified quality.
Issue 4 - Reverse Osmosis is Extremely Slow
The Reverse Osmosis process is very slow compared to its relatively large size system. If the situation requires quick response and output then R.O. is not the ideal choice.Issue 5 - Reverse Osmosis uses a lot of Electricity
The Reverse Osmosis system places heavy demands on electricity in order to provide clean drinking water. A system which is supposed to improve environmental conditions is essentially offsetting its pollution in another form, which does not improve the carbon footprint of users.
See an electricity comparison with another solution
Issue 6 - Reverse Osmosis uses Chemicals to Clean Water
Reverse Osmosis needs chemicals in order to treat drinking water, these chemicals not only cost a lot of money, they are also bad for health and the environment. Here is a list of a few chemicals that a typical R.O. unit may use: membrane antiscalants and scale inhibitors, membrane preservatives, cleaners, biocides and disinfectants, flocculants, corrosion inhibitors, and de-chlorinators. Mostly, all of the disinfectants except chlorine are expensive, however chlorine is not recommended due to its property of reacting with organic contaminants and generating toxic by-products.
Issue 7 - Reverse Osmosis Wastes a Lot of Water
The objective of a water treatment system is to clean water, not to waste it. It is roughly estimated that a Reverse Osmosis machines wastes 3 gallons of water for every gallon it produces. This inefficiency not only means wasted time, but also a lot more electricity and pollution.
Issue 8 - Must be Compatible with the Water Supply
The R.O. system must be matched to the incoming water supply in order to obtain high levels of purity. This means that whether or not the water is already chlorinated and can often have associated installation costs for the buyer.
Issue 9 - Reverse Osmosis Concentrates Dangerous Chemicals
An American Medical Association (AMA) publication has found that Reverse Osmosis was found to concentrate dangerous heavy metals mercury and aluminium, which can be linked with extensive neurological disorders. Nearly every municipal water system uses aluminum compounds in water treatment process.
Issue 10 - Reverse Osmosis units cannot filter out pharmaceuticals
An increasing problem is the pharmaceuticals in drinking water. Unfortunately, R.O. systems cannot filter out these small molecules as they simple pass through the porous membranes of the R.O. filter meaning that it ends up in the final water product.
See a video describing the pharmaceuticals in water
Issue 11 - Creates acidic water & strips minerals
Reverse osmosis, like distillation, creates fairly acidic water, and it also strips the water of important minerals. Additionally, it is contended that R/O destabilizes the molecular structure of water.