Can Reverse Osmosis Remove Salt from Water?

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Reverse osmosis is one of the most popular methods of removing contaminants from water. It eliminates up to 99% of impurities from water, including nitrates, lead, asbestos, fluoride, and TDS, among others.

So, can RO remove salt from water? Yes, reverse osmosis can eliminate salt and other contaminants from water.

But why remove salt from your water when it is essential and crucial for your health? You might wonder.

Well, too much of anything is usually not a good thing. The Dietary Guidelines for America suggest that you should not take more than 2,300 mg of salt per day.

How Does Salt Get into Your Water?

Salt can get into your drinking water by seawater getting into lakes, rivers, or reservoirs. It can also be added to the water by a water softener.

To produce softened water, the water softener adds softening salt to the water.

What are the Effects of Consuming Excessive Salt on Your Body?

According to the Centers for Disease Control and Prevention, salt can have the following effects on people.

  • High blood pressure

Ingesting excessive salt can result in the absorption of more salt in your body. This causes a rise in your blood volume, which leads to high blood pressure.

According to CDC, an uncontrolled rise in blood pressure can lead to cardiac failure, renal damage, strokes, and blindness.

  • Heart disease

As aforementioned, taking too much salt can result in high blood pressure. Should this continue for a long time, it could lead to heart disease. That is why heart disease patients get recommended to avoid salt.

  • Liver issues

Excessive consumption of salt can cause liver problems. It can produce a number of changes in the liver, including increased cell death, malformed cells, and slowed cell division.

  • Stroke

A high salt intake is linked to an increased risk of stroke. In fact, a study conducted by the Northern Manhattan Study shows that individuals who consumed more than 4000 mg of salt daily had a higher risk of stroke.

How Does Reverse Osmosis Remove Salt from Water?

A reverse osmosis system is a water filtration unit that filters water in different stages. It usually has a sediment pre-filter, a carbon filter, an RO membrane, a post-filter, and a remineralization filter (optional).

As water moves through the system, each filter stage eliminates a different set of contaminants. The filters, however, cannot remove tiny particles like dissolved salts.

That is where the RO membrane comes in.

The semi-permeable membrane features a pore size of about 0.0001 microns. The pores are tiny enough to block the larger molecules of dissolved salts.

The salts are then flushed down the drain with wastewater.

How Else Can You Remove Salt from Water?

Although reverse osmosis is the best method to remove salt from water, it is not the only option. Other forms of removing salt from water include:

  • Distillation

Distillation is the process of separating contaminants from water through boiling and condensation.

During the process, water is boiled until it evaporates, leaving behind impurities like salt, which do not have the same boiling point as water.

Distillation produces clean water and is thus an effective water treatment method. The only drawback is that it takes longer than reverse osmosis to produce water.

  • Electro-dialysis

Using electricity, it is possible to remove salt from water. All you need to do is submerge a negatively charged cathode and a positively charged anode in water and separate them with a porous membrane.

The electrical charge of the anode and cathode pulls dissolved ions that make salt towards them like magnets leaving behind pure water.

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Dr. Peter Gleick

Dr. Peter Gleick is an experienced water filtration engineer and technical writer for He is an expert in water purification and filtration, focusing on helping people get clean, safe, and healthy water for domestic use. He has more than 10 years of writing experience and has numerously contributed to leading publications in this field.

1 thought on “Can Reverse Osmosis Remove Salt from Water?”

  1. Is a reverse osmosis system simply better than a DIY 3-stage filtration system by the same company?

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