How to Adjust the pH of Reverse Osmosis Water
Written by: Gene Fitzgerald // Last Updated: Jul 26, 2023
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Reverse osmosis water is great in many aspects. However, it also has a few peculiarities which are important to understand and adapt to, especially if you’re planning on drinking reverse osmosis water frequently.
The pH level of water that’s been treated in this manner is of particular importance. Reverse osmosis water is slightly acidic by default, and you should know your options for adjusting it…
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Key Takeaways
- Adjusting RO water pH can be done in various ways, depending on whether you want to increase or decrease the pH level.
- You can reduce RO water pH by removing the remineralization filter from your reverse osmosis system (if there is one), add food-grade acids to the water, process the water using anion exchange resin, or using an acid injection system.
- You can increase RO water pH by adding a remineralization filter, using an alkaline water pitcher, adding mineral drops to the water, sending the water through a water ionizer.
How to Adjust the pH of Reverse Osmosis Water
So, how to adjust the pH of reverse osmosis water?
You can freely adjust the pH level of reverse osmosis water in either direction if you’re unhappy with its default state. There are various options available in both cases – increase and decrease – and many of them can be bought over the counter at a local store.
In a nutshell, here is how you can reduce RO water pH:
- Remove the remineralization filter if there is one.
- Add food-grade acids to the water.
- Process the water using anion exchange resin.
- Use an acid injection system.
In a nutshell, here is how you can increase RO water pH:
- Use a remineralization filter.
- Use an alkaline water pitcher.
- Add mineral drops to the water.
- Send the water through a water ionizer.
How to Reduce the pH of Reverse Osmosis Water
Reducing the pH level of reverse osmosis water means making it more acidic. This can be as simple as adding some acid to the water, or it can involve some adjustments to your current system. Here are some of the most popular options to consider.
Ditch Remineralization
Are you using a remineralization filter in your reverse osmosis system? Simply removing it should be enough to reduce the pH level of your reverse osmosis water significantly. You shouldn’t have to do more than that in most cases, as this change alone should have a noticeable effect.
Don’t be quick to throw away the whole remineralization filter though – you should start by just disconnecting it temporarily to see how it changes things.
Lemon Juice and Other Food-Grade Acids
You can add some lemon juice or another type of food-grade acid to your RO water to make it more acidic. Just a few drops should be enough. In fact, you can reduce the pH level of a gallon of regular water by as much as 0.5 with just a couple of drops of lemon juice! Feel free to use an alternative food-grade acid if you don’t want to use lemon juice specifically for whatever reason.
Anion Exchange
An anion exchange system often reduces the pH level of regular water.
If this works in the same manner with RO-purified water is questionable. That’s because most anions have already been removed from the water. Still, might be worth a try!
Acid Injection
Finally, you can also consider using an acid injection system. However, that’s often not an option for most households, as these systems usually treat water at the point of entry, so before the reverse osmosis system.
How to Increase the pH Level of Reverse Osmosis Water
Alternatively, you might be interested in ways to increase the pH level of your reverse osmosis water – or make it less acidic. Just like the opposite, this is also possible with various commonly available tools and supplies.
Remineralization
A remineralization filter is one of the most commonly used approaches for this. It’s an additional filtration stage, typically added to the end of the chain of a reverse osmosis system, which adds minerals to the water to replenish the ones that were taken away during the reverse osmosis process.
Remineralization filters add minerals like calcium, magnesium, and potassium which you’d normally naturally find in water in some amounts.
Alkaline Pitchers
An alkaline pitcher is also a great option for increasing the pH of reverse osmosis water. There’s nothing special about this – you just pour water into the pitcher, and it dispenses water with a slightly higher pH level. The only downside here is that you have to refill the pitcher manually.
Mineral Drops
Many general purpose stores sell mineral drops that you can add to your water to increase its pH level. These are often used by people concerned about the low mineral content of water treated with a reverse osmosis system. A great thing about mineral drops is that they allow you to control how much you want to decrease the acidity of your water.
Water Ionizers
Water ionizers are another option, although they’re not as commonly available as other methods on this list. There are also some dubious claims about the exact effects of water ionizers on our health, so make sure to do your own research before investing in something like that.
Further Reading:
What Is the General pH Range of Reverse Osmosis Water?
In general, reverse osmosis water has a pH level of between 6 and 6.5. You won’t find many variations to this, as the process is pretty consistent across the board and always produces similar results. This means that you should be able to easily adjust the pH level of your reverse osmosis water since you’ll have a good idea of what you’re starting with.
Why Most Reverse Osmosis Water Is Slightly Acidic
Why is reverse osmosis water slightly acidic in the first place though? It’s mainly because it has no mineral content or other impurities, leaving you with pure, clean water and nothing else.
You would expect such water to be neutral (neither acidic nor alkaline). However, pure water dissolves CO2 from the surrounding air forming carbonic acid. Carbonic acid might be a weak acid, but it’s still enough to make RO water acidic.
How to Test RO Water pH
There are various ways to test the pH level of reverse osmosis water. Some of the simplest and most widely available ones include pH test strips and digital pH meters.
pH Test Strips
Using a pH test strip is very straightforward. You simply add water to the strip and watch the indicators. The strip will tell you your RO water’s pH range.
Digital pH Meter
A digital pH meter is a step up from using a pH test strip. It gives you more precise information about the state of your water, and is also reusable, allowing you to test your water multiple times as you make adjustments to your system.
If you have any questions about reverse osmosis pH adjustment please don’t hesitate to leave a comment below!
About the Author Gene Fitzgerald
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