How to Safely Make Reverse Osmosis Water Alkaline at Home

Last updated Nov 29, 2021

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Good morning, I’m your host, Pete, the creator of AWMS & confirmed water-o-holic. One of the downfalls of RO systems is they tend to make drinking water acidic. In this guide, I show you several easy ways to make your reverse osmosis water alkaline at home.

I’ve started my day with several cups of pH 8.5 ionized water and my special stash of green tea.

Needless to say, I’m feeling fresh and full of energy to deliver you the best possible tutorial.

Let me start off by saying that reverse osmosis filtration does an incredible job of purifying water, almost too good.

Let’s kick things off by discussing the average pH of plain reverse osmosis water.

What is the pH of RO water?

RO systems do an amazing job of filtering everything from water because of the RO membrane’s microscopic pore size.

RO systems strip all the minerals from your tap water, including the alkaline minerals that act as pH buffers and stabilizers.

Once the minerals are stripped away, you’re left with slightly acidic “blank” drinking water. And blank water loves to absorb whatever it can.

According to this engineering forum, reverse osmosis filtration removes the alkaline buffers from water while leaving carbon dioxide (CO2) intact.

Then, the carbon dioxide turns into carbonic acid, which lowers RO water pH.

Top RO companies have caught onto this, which we’ll go into in greater detail in the following section.

Reverse osmosis water usually tests between pH 5.0 to 7.0

Now that you know why reverse osmosis water is acidic, let’s go over how to make reverse osmosis water alkaline.

How to Make Reverse Osmosis Water Alkaline

You already know that reverse osmosis water has little to no minerals in it, so the best way to raise RO water pH is to add alkaline minerals back to it.

The perfect solutions are RO systems with remineralization or the addition of an RO remineralization cartridge to your existing system.

Over the past couple of years, plenty of new RO remineralization filters have popped up, so you’ll have no problem finding one online.

We prefer RO mineral filters made with US-sourced, FDA-approved materials.

Cartridges typically include alkaline minerals magnesium, sodium, calcium, and potassium.

Our current favorite RO mineral filter is made by APEC water systems.

APEC Water Systems uses high-purity calcium carbonate sourced in the US for its cartridges.

Expect a pH increase of .5 to 1.2 after installing a mineral filter catridge

Always be sure to test the pH of your water with pH test strips or preferably a digital meter before and after installation. This way, you know whether the remineralization filter is doing its job and the original pH of your plain RO water.

Remineralization filter life is usually 6 months or every 1500 gallons.

APEC provides mineral filters with 1/4″ and 3/8″ quick-connect fittings, so be sure to match the filter size to your existing system before you order one.

If the filter you want is available in one size only, there’s the option to use 1/4″ to 3/8″ fittings available at Amazon #ad:

Complete RO System Options

If you don’t already own an RO system or want to replace your current one, our guide to choosing the best reverse osmosis system with remineralization is an excellent resource.

Several of the most trustworthy water filter brands are:

  • APEC Water Systems
  • iSpring
  • Express Water
  • Home Master

All four of these brands manufacture complete RO systems with remineralization. To get the best-tasting remineralized RO water, we recommend:

Home Master TMAFC

This is one of the few systems on the market that delivers consistent bottled-water quality water on tap at home.

How to Make Reverse Osmosis Water Alkaline with a Water Ionizer

While remineralization filters will boost your pH, you may still want to raise your pH higher.

The problem is that most of the time you won’t be able to get past pH 8.5 with a mineral filter.

If your goal is to reproduce Essentia Water – which has a pH of 9.5 – at home, you’ll need to use a water ionizer.

The good news is that water ionizers are compatible with remineralized RO water.

The bad news is water ionizers are not compatible with plain RO water because there needs to be a minimum number of minerals in your feedwater for the ionizer to work properly.

Another consideration is the total cost of using both a water ionizer and RO system.

Is it worth it? That’s debatable.

It’s up to you whether you want to boost your drinking water pH beyond where a remineralization filter takes you.

For most folks, a slightly alkaline pH is just fine.

If you’re new to ionized water, Air Water Life manufactures a good budget ionizer that works with remineralized RO water.

Final Thoughts

The best way to make reverse osmosis water alkaline is through remineralization.

If you already own an RO system, adding an RO mineral filter as the final stage in your system will raise pH by about a full point.

If you’re unsatisfied with the resulting pH, the next option is to consider purchasing a water ionizer.

Water ionizers give you full control over the pH of your water. Additionally, they offer you the widest pH range.

All in all, it’s best to stick with these methods rather than alternative methods, e.g. baking soda, because the methods in this guide are the best long-term solutions.

Lastly, consider picking up a pH pen and TDS meter if you don’t already own them. These instruments ensure you’re getting the results you desire and are within the recommended pH and TDS ranges for drinking water.