content is free. We earn a commission at no extra cost when you purchase through referral links on our site.
Learn more

Does Reverse Osmosis Remove Sodium From Softened Water?

does reverse osmosis remove sodium from water


Sodium, calcium, and magnesium, being essential components, play an important role in our body, but their higher levels can cause various issues. They can enter your water supplies through geological sources. 

You might use a water softener to remove the minerals to make water softened, resulting in increased sodium content. After that, you can pass the water from the RO membrane. The reverse osmosis membrane will easily remove high levels of sodium from the softened water up to 95%. 

This article will explore the practical approach for lowering salt/sodium levels with the help of reverse osmosis filters and ensuring safe drinking. Let’s begin!

Does Reverse Osmosis Remove Salt From Softened Water?

Does Reverse Osmosis Remove Salt From Softened Water

Your water might have little salt, and you will likely consume too much of it. However, if you are on a low-sodium diet or if you need to limit your sodium consumption for another reason, like high blood pressure, you can reduce it. Various methods can meet this goal, and reverse osmosis is one of them. 

Reverse osmosis (RO) can effectively remove salt, including sodium ions, alone from drinking and seawater. However, the salt or sodium removal from softened water depends on the specific situation of your water treatment system. Let me explain how.

Sodium is also considered a mineral that can be present naturally through groundwater and added from water softeners on the other side, too. Water softener uses gelatinous resin beds, which are made up of sodium ions. Instead of removing them, it adds sodium ions to drinking water by replacing them with mineral ions. As a result, the water becomes “soft” but slightly high in sodium content.

Now, after the ion exchange or water softener, if the reverse osmosis media is installed and water is allowed to pass through an RO membrane, It will remove dissolved sodium content up to 90-95%.

In summary, water softening is not crucial; if your water has high sodium content, a reverse osmosis water filtration system is enough to produce high-quality water for drinking, cooking, and various industrial applications. Besides, it can also be used for desalinating seawater to make water suitable for drinking and irrigation.

Click to Learn a Complete Guide:

Does Reverse Osmosis Soften Water?

Reverse osmosis (RO) can remove minerals responsible for hardness to a good extent. Still, it is not typically used as a primary method for water softening. Excess hardness in your water can affect the RO membrane same as appliances. It can cause scaling, damaging the membrane, and reducing its lifespan and quality.  

On the other side, water softening is specially made to remove the hardness of minerals like calcium, magnesium, and zinc from water. It works on the mechanism of ion exchange resin, which replaces mineral ions of water with sodium/potassium ions of the resin bed, resulting in more salty water. 

In comparison to water softeners, reverse osmosis is commonly used to remove dissolved salts, arsenic, lead, nitrates, bacteria, amoeba, and even minerals through a semi-permeable membrane.

Ultimately, we wouldn’t recommend RO if you want to reduce hardness significantly, so a dedicated water softener is usually a better choice in this scenario.

Click to Learn a Complete Guide:

Do You Need a Water Softener With Reverse Osmosis?

Whether you need a water softener with a reverse osmosis (RO) system depends on the specific water quality in your area and your desired water treatment goals. Combining a water softener with a reverse osmosis (RO) system is a common and effective approach if your water has multiple quality concerns.

Typically, in this combination, the water softener is installed upstream to remove calcium and magnesium. Then, the softened water enters the RO system, where sodium and other impurities are reduced.

Various advantages of using this combination are mentioned as:

  • Prevent scale buildup in plumbing and appliances
  • Reduces soap scum
  • Improves the cleaning capabilities of soap and detergents. 
  • No taste of salty water
  • Protecting the water-using appliances
  • Extending the lifespan of RO membranes

You may need to maintain the treatment systems regularly. The resin beads get saturated with the ions, which require periodic regeneration or resin replacement to restore working capacity. At the same time, the RO membrane and filters need to be replaced after 6-8 months.

What is Sodium in Drinking Water? 

Sodium plays an important role in maintaining body fluids, regulating blood pressure, transmitting electrical signals in nerve cells, and playing a role in muscle contraction. Plus, It is involved in the transport of various nutrients, such as glucose and amino acids, across cell membranes.

1. Safe Levels of Sodium

EPA recommends the levels of sodium shouldn’t exceed 20 mg/L for a person with a low sodium diet. For normal individuals, it shouldn’t be more than 30 to 60 mg/L.  

2. Health Effects of Sodium

The long-term consumption of elevated levels is associated with various health effects, such as chronic congestive heart failure, High blood pressure, Heart or circulatory disease, and Kidney difficulties. Further, some evidence claims that it damages the heart, aorta, and kidneys without increasing blood pressure. 


In a final verdict, if you’re concerned with the sodium content in drinking water, reverse osmosis (RO) can work well for you. In a typical water treatment setup, softened water initially contains an increased level of sodium due to the ion exchange process used in water softeners.

When the softened water is passed through an RO system, it can efficiently remove sodium ions along with other impurities, ensuring low-sodium water for drinking and various household uses. This combination of a water softener followed by an RO system is a comprehensive approach to address both hardness and sodium concerns from the water supply.

Scroll to Top