Why Does My RO Water Taste Bitter? (+ How to Fix)

This page may contain affiliate links. If you buy a product or service through such a link we earn a commission at no extra cost to you. Learn more.

As a rule, reverse osmosis water should have hardly any flavor. It is pretty bland, as impurities in water are what give it taste.

So, if your RO water has a bitter flavor, it’s a sure sign that something is amiss.

Let’s look at what might be happening and how to fix it.

Key Takeaways

There are various reasons that RO water may taste bitter, each with its own solution.

  • Corroding Copper Pipes – Use remineralization before the purified water comes in contact with the copper. You could also replace the copper pipes with plastic.
  • Old Reverse Osmosis Membrane – Replace the membrane with a new one.
  • Leaching RO Storage Tank – Replace the tank or opt for a remineralization filter.
  • High Sulfur/Salt Levels in the Source Water – Consider additional prefilters or replace the filters and membrane.

Why Does My RO Water Taste Bitter?

“Why does my RO water taste bitter?”

There are several reasons why your reverse osmosis water may taste bitter.

If your RO system is not effectively removing all salts from the water, it might be time to consider using additional pre-treatment or, if you haven’t for a long time, replace the reverse osmosis membrane which might have reached the end of its service life. A bitter taste in reverse osmosis water may also indicate copper pipe corrosion or a leaching storage tank.

It is crucial to identify the specific problem to address the issue, as pinpointing the cause will expedite the repair process and ensure faster access to better-tasting water.

Corroding Copper Pipes

Numerous plumbing systems use copper tubing that can leave a metallic aftertaste in the water, resulting in bitterness. And because reverse osmosis water is exceptionally pure and slightly acidic, it tends to pick up even more bitterness when it comes in contact with copper pipes.

Now, corroding copper pipes is usually only a problem for people using a whole house reverse osmosis system, as under sink or countertop models usually feature plastic tubing. The only point-of-use application that can be problematic is when you connect your RO system to the refrigerator or ice maker which often use copper tubing.

Old Reverse Osmosis Membrane

The primary filter in an RO system is the semi-permeable membrane, equipped with 0.0001-micron pores that efficiently capture most impurities.

However, regular replacement is crucial so that it does not clog. Failure to address a clogged membrane in your RO system can lead to impure water, leaving behind unpleasant dissolved solids that alter the taste and may make it bitter.

blue reverse osmosis membrane

Leaching RO Storage Tank

The strange taste in your RO system could be coming from the storage tank itself. If your RO system has a butyl bladder in the storage tank, the filtered water may absorb taste and odor while it waits for use.

After removing minerals, RO-filtered water can leach substances more easily than tap water, particularly if it has been sitting in the storage tank for a while.

High Sulfur/Salt Levels in the Source Water

A high concentration of sulfur from the feed water can result in a lingering unpleasant taste. The filters or membrane probably require replacement if a water test reveals a bitter taste attributed to elevated sulfur levels.

Dissolved salts and solids in the water may also give it a salty and sour taste. A properly functioning reverse osmosis system should effectively remove all forms of total dissolved solids from the water. If this is not occurring, there may be an issue with the filters or membrane.

How to Fix Bitter Tasting RO Water

Once you have identified the cause of the bitter tasting water, follow one of these solution pathways to fix it:

  • For corroding copper pipes: You should remineralize the water properly after treatment. This way, the water is no more acidic and doesn’t leach copper. By the way, this works for both point-of-use and whole house applications. You could also replace copper with plastic, but it’s going to be expensive.
  • For an old RO membrane: To prevent the inconvenience of unpleasant-tasting water, replacing the semi-permeable membrane every two years and all other filters every 6 to 12 months is crucial. These routine maintenance tasks are necessary for maintaining the high water quality in an RO system.
  • For a storage tank issue: If you haven’t used your tap for a while, flush out the tank and check if the taste disappears. Many people also use a remineralization filter to eliminate any lingering flavors after the water leaves the tank. If these steps don’t resolve the problem, there may be an issue with the storage bladder inside the tank, and replacing the tank might be necessary.
  • For high salt levels: Replace all filter elements. Stay on track with the filter replacement schedule. If your feed water is exceptionally high in salt, then consider additional pretreatment.

What Should Reverse Osmosis Water Taste Like?

Water treated with reverse osmosis has a distinct flavor, sometimes described as a lack of flavor or ‘bland’ compared to regular tap water.

The elimination of chemicals and impurities like minerals leads to a noticeable change in taste. Reverse osmosis water is typically devoid of any taste, so if it suddenly presents with a strong taste of any kind, it usually suggests the need for maintenance or a malfunction in your RO system.

If you have any questions about why RO water tastes bitter please don’t hesitate to leave a comment below!

About the Author Gene Fitzgerald

Gene Fitzgerald is one of the founders of BOS and currently head of content creation. She has 8+ years of experience as a water treatment specialist under her belt making her our senior scientist. Outside of BOS, Gene loves reading books on philosophy & social issues, making music, and hiking.
Learn more about .


Information provided on BOS is for educational purposes only. The products and services we review may not be right for your individual circumstances.
We adhere to strict editorial guidelines. Rest assured, the opinions expressed have not been provided, reviewed, or otherwise endorsed by our partners – they are unbiased, independent, and the author’s alone. Our licensed experts fact-check all content for accuracy. It is accurate as of the date posted and to the best of our knowledge.

Leave a Comment: