Understanding The PH of Reverse Osmosis Purified Water

As an Amazon Associate I earn from qualifying purchases. Learn more.


One of the reasons people are skeptical about investing in a reverse osmosis purification system is that they have concerns about the pH level of the treated water.

We hope to clarify all your misunderstandings regarding the pH of reverse osmosis purified water with this post. This will help you make a more educated decision regarding which purification system to invest in.

Understanding pH and its importance for drinking water

PH of Reverse Osmosis Purified Water

pH stands for potential hydrogen, which represents the number of free hydrogen ions in any solution. In simpler terms, it is the measure of the acidity or basicity of any solution.

If water has an equal amount of H+ and OH– ions, its pH remains neutral.

If the number of free H+ ions increases in water, the pH decreases, and it becomes more acidic.

Similarly, increased concentration of OH- ions yields a more alkaline water pH.

The pH scale ranges from 0 to 14, where 7 is neutral, 0 is highly acidic, and 14 is highly alkaline.

Typically, in our bodies, the pH level is maintained as slightly basic.

Water which is too acidic or too alkaline is unhealthy to consume. But slight acidity or alkalinity of the water you consume on its own is unlikely to affect your body’s pH. 

Comparison of different pH levels

LiquidpH level
Black coffee5 pH
Mineral water7.5 pH
Reverse osmosis water5-7 pH
Tap water6-8 pH
Tomato juice4 pH
Vinegar2 pH

Is acidic water bad for you?

It is true that, over time, consuming acidic water can be bad for your health, but this is when the acidic water interacts with heavy metals that may be present in the water.

Slight fluctuation in the water is completely normal as research suggests that the pH of most natural water in the US ranges from 6.5 to 8.5.

We consume beverages with a wide range of pH, such as coffee (5 pH), soda (2.5 pH), sports drinks (2.5 pH), etc. It is better to avoid soft drinks, soda, and similar sugary drinks for better health, but it is vital to know that slightly acidic water is not the end of the world.

The human body can effectively maintain the blood pH level as long as we have a balanced diet.

 How is reverse osmosis water acidic?

PH of Reverse Osmosis Purified Water

Reverse osmosis purified water is slightly acidic and has a pH of 5-7.

This is because semi-permeable filters of a reverse osmosis purification system remove several contaminants like heavy metals, microplastics, etc., but they are unable to filter out carbon dioxide.

Carbon dioxide may dissolve in water, making it slightly acidic once it passes through the filters.

On the other hand, mineral water is not acidic as it has other compounds to balance out the pH difference.

RO water is healthy!

Reverse osmosis is the most effective and efficient way of purifying drinking water.

Reverse osmosis treatment systems have several filtration systems that remove up to 99% contaminants like chemicals, herbicides, heavy metals, pesticides, etc., from tap water to make it safe and clean enough for consumption.

RO systems undoubtedly provide the best-tasting and quality water out of all the different water treatment systems.

The pH level of reverse osmosis purified water is between 5-7 pH, which lies within the healthy water pH range. Slightly acidic pH might be of concern if your water has heavy metals like contaminants.

However, reverse osmosis effectively removes heavy metals and several other contaminants.

Consuming untreated or unfiltered water can cause several diseases or health concerns, but a reverse osmosis purification system can save you from them.  

Can you increase the pH of RO water?

You can increase the pH of RO purified water if it is less than what you prefer simply by adding an alkaline filter stage to your RO purification system. This will be the last stage of the purification system and will add some minerals back to the water to slightly increase its pH.

Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.