Is Reverse Osmosis Water Good for You (Pros and Cons)?

Reverse osmosis is a process used to purify water. It’s also referred to as an RO system.

Most of us are familiar with regular osmosis – the process where water molecules move through a partially permeable membrane from a solution with a high concentration of water molecules to one with a lower concentration.

As its name implies, reverse osmosis reverses this process. It uses pressure to force water through a semi-permeable membrane, separating it from dissolved inorganic solids like salts, minerals, and contaminants.

It is a highly effective procedure, removing up to 99% of contaminants, and was originally used to desalinate seawater in order to make it drinkable. 

The technology – once only available to government, military, or commercial organizations – is now available for residential use too, and it is affordable to buy a reverse osmosis water system for use in your own home.

Most people use their reverse osmosis water filter to turn city or local tap water into filtered water.

Water filter pitchers

A water filter pitcher has a filter installed inside the lid to cut down on the number of contaminants in the water.

The filter may be a physical mesh, fine enough to capture dirt, sediment, and other particles.

But sometimes the filtration is via absorption, using a substance like activated carbon in carbon filters to attract and trap certain contaminants from water systems. 

Water filter pitchers don’t need any electricity and are both cost-effective and easy to use. They also retain all of the water’s healthy minerals, because they don’t remove dissolved organic matter in the same way that reverse osmosis does.

Sequestration filters

Sequestration is the chemical isolation of a substance. 

In terms of water filtration, polyphosphate is used to stop the calcium and magnesium in water from forming limescale on the surfaces it touches. 

However, it doesn’t actually remove these minerals from the water altogether and is mainly used to prevent corrosion in appliances.

Ion exchange filters

These soften water by using electronically charged solids to remove contaminants. They usually have inlet and outlet valves going to and from a filter tank, mesh filters to prevent any solids from escaping, and some type of ion exchange resin. 

Ion exchange filtration is considered a sustainable process that removes a broad range of contaminants, improving both the quality and taste of water.

Almost all contaminants are removed from the water

Unlike other water filtration processes, reverse osmosis eliminates around 99% of contaminants including heavy metals and other potentially harmful contaminants – and that applies to high-quality systems designed for home use, too.

This is because the reverse osmosis membrane filter is capable of removing dissolved substances, whereas most other filtration systems are only able to capture larger contaminants. 

So effective is the procedure of RO filtration that its use has replaced the need to boil water in communities with no access to safe drinking water.

It meets the need for mineral-less water

Because the water produced by reverse osmosis is about as pure as you can get, it is ideal for situations where mineral-free water is required.

One example would be for use in home aquariums, where aquatic pets benefit from water completely free of added minerals and contaminants.

It can also have culinary applications. Chefs have noted that the presence of minerals such as added fluoride can affect the flavor of certain dishes, while connoisseurs of coffee feel that these minerals prevent the proper extraction of flavor from coffee bean oils.  

It cuts down on the plastic waste associated with bottled water

In areas where access to clean drinking water is restricted, the solution has historically been to use bottled water instead.

This, of course, creates vast amounts of plastic waste.

Reverse osmosis eliminates the need for plastic bottles, minimizing the risk of pollution.

See my related article about the healthfulness of Smart Water.

The flavor won’t suit everyone!

Because we are accustomed to water containing minerals, totally demineralized water from an RO membrane can taste quite “flat” in comparison.

However, many modern reverse osmosis systems will include a remineralization stage to restore the beneficial minerals that give “regular water” the taste we enjoy and are used to.

Reverse osmosis systems can be expensive

Reverse osmosis technology was originally designed to be used on a large scale – for military or commercial use, for example. Use on this scale justified the cost of installing such systems. 

For the domestic consumer, however, reverse osmosis filtration can be expensive.

Depending on the system you choose, there may be costs involved with the initial installation, followed by regular ongoing maintenance of reverse osmosis filtration systems (usually annually).

There will also be some waste involved as the RO filters with the semipermeable membrane will be discarded.

The reverse osmosis process wastes water

As mentioned earlier, this method of filtration helps the environment by cutting down on waste plastic. 

On the flip side, however, is the fact that larger reverse osmosis systems waste water – anywhere from 3 to 20 times as much as they produce. 

This is both environmentally harmful and expensive for the consumer.

India’s government actually banned the use of reverse osmosis filters in 2020 in areas where they are not absolutely necessary, in order to reduce water and energy waste. 

However, no such ban exists elsewhere in the world. 

Healthy minerals are removed along with contaminants

Reverse osmosis is so effective that it removes virtually ALL minerals from the water – even the ones that are good for the human body.

These include magnesium, calcium, and potassium, along with the fluoride that is added to community water supplies to support dental health.

However, there is little recent research into just what effects the long-term consumption of demineralized water might have on our health.

An older report from the World Health Organization, however, concluded that:

“Demineralised water that has not been remineralized, 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.”

It makes sense, then, to choose a reverse osmosis system that remineralizes the water after purification to ensure that you and your family get adequate mineral intake.

The PH level decreases

When minerals are stripped from water, its PH level lowers and it becomes more acidic. This isn’t harmful to our health but it can be damaging to the pipes and storage tanks in our homes, potentially causing toxic metals to leach into our water.

Again, remineralization can prevent this issue and restore the water to its correct PH level.