Do remineralizing filters really work?

Do remineralizing filters really work?

The short answer is no.

Many companies suggest that because reverse osmosis systems remove the minerals from water that you should add a remineralizing filter afterwards for the purpose of restoring minerals to your water.

I’ve tested these filters and while the pH rose dramatically due to carbonates in the filter there were no minerals added.  A number of companies use coral calcium as the remineralizing filter and it is true that coral calcium contains some 70 trace minerals.  The problem is that the water passing through a filter system is not in contact with the coral calcium long enough to dissolve it.   The water picks up carbonate and as a result the pH increases but essentially no minerals are added.

So, what should you do about the lack of minerals in your reverse osmosis water?

Don’t worry about it.

I’ve now done substantial testing of water and minerals and concluded that while it would be nice to have minerals in your water, it’s far more important to remove the contaminants.  You can read a referenced article on that topic here: Minerals in Water.

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About James McMahon

Studied ecology at the University of Illinois, mountain survival at Eastern Washing University, Deep Ecology at Naropa, River Ecology with The Nature Conservancy and Luna Leopold
This entry was posted in Best Water Filter, Exposure to Toxins, Healthy Drinking Water, Reverse Osmosis, Sweetwater LLC, Water Purification. Bookmark the permalink.

33 Responses to Do remineralizing filters really work?

  1. Mark says:

    You need to remineralize the water because drinking acidic water is unhealthy. It will at the very least, demineralize your teeth, possibly causing you to break one on a hard peanut, or something.

    • Hi Mark,

      I appreciate your comments but that wasn’t the point of my post. The remineralizing filters that I have tested do not add minerals back into the water. That was my point. They are hype, as far as I can tell. If there is one that is working I would love to hear about it.

      They do raise the pH – too much in my opinion. And that is really what you’re addressing here when you talk about ro water being acidic. RO water is acidic and I think it is healthy to raise the pH slightly, to a pH of 7.4 or thereabout, to make it slightly alkaline. I do that in the RO systems I sell by using a calcite filter. Many remineralizing filters raise the pH to 9 or higher and that is unnatural and in my opinion unhealthy…maybe even dangerous.

      As for demineralizing your teeth, and possibly your bones, that is an area I am researching further. I don’t think that water has much to do with it but am open to learning differently. I do think that aging and diet are key factors. Again, thanks for commenting.

      • Kate says:

        Are you still searching for the answer?

        Heavy metals and aluminum in particular are to blame. When Fluoride is combined with aluminum from food (processed food for example), it removes Iodine from our cells and possibly other minerals.
        I’ve had enlarged thyroid my whole life. I switched to RO water (the only water that filters our fluoride completely) and stopped using fluoride toothpaste. And my thyroid got back to its normal size.

        I do have high aluminum in my body. Hence, cannot drink water with fluoride. Fluoride gets attached to aluminum and removes iodine from our organs and cells messing up enzyme production.

        Unbelievable, someone in 1940s did a research on mice, found out that adding fluoride to water is somewhat beneficial and since then, we’ve been drinking poisonous water.

        Cancer, autism, Alzheimer’s, Parkinson’s, MS, and many other health problems have been on the rise since 1940.

        This is an answer to your search and your question.

        To detox from aluminum, you can drink high silica water, such as Fiji water.

        • Actually RO water would detox you from aluminum.

          • Dan says:

            Elsewhere on this site, you said the idea that “drinking [RO water] will strip minerals from your body… is nonsense. The body does not work this way.” Are you attempting to differentiate between beneficial minerals and toxic metals?

          • I’m not sure I understand your question. Clearly minerals in water are different than toxic metals. I’m saying that removing minerals from water doesn’t negatively affect your health. One would often use RO due to the contaminants in your water including toxic metals, nitrates, arsenic, and high total dissolved solids.

  2. Bruce says:

    I am not a chemist, and my understanding of the science is insufficient to enable me to draw my own conclusions based on the science, but I am ok at critical thinking and I like what I read on your blog.

    I am in the process of designing my own home water treatment (RO) and I would like to talk to you; specifically about re-mineralization.

  3. Joseph Moreno says:

    What if you have an expensive esspresso machine? Manufacturers don’t want you to use Reverse osmosis because the machine depends upon the minerals to function properly but they also don’t want you to use tap water because the water is very hard and would require more frequent descaling which would be a hassle especially if you buy a machine that requires you to send the machine to a company to descale it.

    So what would be the best filter to use?

    • It is my understanding of coffee making that the presence of minerals contributes to better taste and lower acidity, but I do not know this for a fact.

      The filter you would use would depend on where you live and the mineral content of the water supply.

  4. Sam says:

    RO water filtration is probably the best. It filters down to 0.0001 micron. Adding a block style activated carbon filter also helps.
    To add minerals back into your water and help to raise the pH, you can add 1/4 teaspoon of Himalayan salt/gal.

  5. Justin Clark says:

    How can the short answer be no when you stated “I’ve tested these filters and while the pH rose dramatically due to carbonates in the filter there were no minerals added”. So does the remineralization propcess not perform pH increase?

  6. ryant says:

    i have well water that is pretty clean now, what would be the benifit from adding a RO system?

    • I would recommend a water test for your well water before purchasing anything. In terms of your question, I don’t know what ‘pretty clean’ means. If it means there are no contaminants, then there would be no benefit to adding an RO.

  7. Herbert de Graaf says:

    We just read up on WHO and other sources, as we use RO since a few years. Our concern about RO water beings to be that not only it does no longer contain good minerals, but especially that RO water that is used for cooking extracts these minerals from the food you cook and, when drunk, extracts minerals from the body which are then disposed through urination. This is why WHO says RO water presents a long term health hazard. What would you say to this?

    • First, the study you refer to is not a WHO study. It is a study funded by WHO in Eastern Europe. The study was published by the National Institue of Public Health in the Czech Republic. I have read that study and every reference in back. Some of these references simply refer to one another.

      Second, the study says nothing at all about RO water leaching minerals from your body or from your food when you cook. I don’t know where you read that nonsense, but that’s what it is. Minerals are not leached from the body by water. Now, if you are out running or working out on a hot day you may wish to drink electrolytes but that is another topic entirely.

      What the study does suggest is a link between drinking low TDS (total dissolved solids aka the minerals in water) water and heart disease. However the study totally ignores other factors including lifestyle considerations, air pollution, happiness, etc. Have you been to Eastern Europe? There are many factors which may affect the rate of heart disease other than drinking water. None of these were considered.

      So I did my own study on cities in the U.S. which have low tds water and the rate of heart disease. You can read that here. Those cities include Seattle, San Francisco, Portland, and Denver. NONE OF THEM have high rates of heart disease. ALL OF THEM have low tds water….from rain and snow in the mountains.

      There is a 1980 WHO study that makes bizaare assertions about minerals being leached from the body. That report went on to recommend the ideal composition of minerals in water. Do you realize that no one anywhere has water with an ideal composition of water.

      We drink the water that is available to use where we live. I don’t worry at all about low mineral content. I think WHO is full of you know what. However, mineral content can be too high, as it is in LA and any city drinking Colorado River water, as well as other similar sources. When mineral content is too high the water will not be hydrating….it will not effectively hydrate your cells. (Read the Wikipedia definition of Osmosis.

      Likewise, when there are pharmaceuticals in your water from cities upstream dumping sewage in your water, or when nitrates are present, or radioactive metals then you need to be drinking reverse osmosis water or you will suffer the negative health effects of these contaminants.

      Too much has been made of these WHO studies. The vibrant health of people in U.S. cities with naturally low tds water directly contradicts their findings. When WHO funds a study in the U.S. on tds I’ll read that. In the meantime I suggest you stop reading nonsense published on the internet. You may find information on my drinking water filters here.

  8. Aaron_c says:


    I’m curious what happens to the minerals (mostly calcium from the calcium carbonate and maybe magnesium from the magnesium carbonate if I understand correctly) after the carbonate dissolves? In my admittedly fuzzy understanding of chemistry if you dissolve an ionic compound like table salt in water then both parts dissolve, not just one. But you say that water put through these remineralizing filters doesn’t receive much in the way of the minerals. What am I missing?

    I’m also wondering about doing some DIY with regards to lowering the acidity of RO water. I’ll be on the road for a bit and I expect that the best water available at a somewhat reasonable price will often be RO water from a machine at a local grocery store. I’d like to be able to reduce the acidity with calcium carbonate as you describe but there don’t seem to be any gravity-fed-type remineralization filters (I won’t have an RV so won’t have water pressure with which to push water through more “normal” filters). Can I just splash a spoonful of calcium carbonate in my 5-gallon jugs before I fill them with RO water? Should I use larger blocks of calcium carbonate, like marble-sized? About how long does the water need to be in contact with the calcium carbonate before it’s sufficiently alkaline?

    Thanks, and thanks for your work on this fantastic blog. I’m finding it very helpful and informative.

  9. joe says:

    Dr Norman Walker invented the first juicer and wrote a book on water. He lived to 100. He said that you should only drink distelled water (ro same). His comment on the mineral content being deminished is that all minerals in the water are inorganic (body cant absorb). and deposit in your connective tissue. If you eat / juice a healthy diet you will get all the organic minerals you need though food.

  10. Bob H says:

    I think the systems with a tank storage will see some minerals added as there is water sitting in the remineralization filter for varying periods of time as water is drawn from the tank in short intervals throughout the day.

    I’m basing this on my observation that the TDS of my RO water after leaving it overnight jumps up to 150 ppm until I’ve flushed it for about 5 or 10 minutes and then it reads around 15 ppm, with or without the remineralization filter.

    That being said, if anyone is concerned about not having minerals, the easiest solution is to add a pinch of epsom salt and/or pink Himalayan sea salt, maybe some sodium bicarbonate, to each gallon of filtered water.

    • Very observant. It does make sense that minerals from the filter would be dissolved as they sit in the low pH water overnight. I would expect the first flush to be heavy in mineral content but then again to have none at all once that water has been drained.

  11. Jim Purcell says:

    I use fossilized coral sand (packaged for marine aquarium use) to remineralize my RO water. I have a large porcelain jar with a stainless steel spigot at the bottom; I rinsed the coral sand, placed it in the jar, and filled the jar with RO water. The advantage of this is extended exposure of low-tds RO water to the coral sand. Also, the remineralized water is denser and heavier, which is perfect as I draw off the water from the bottom through the spigot. I refill with fresh RO water with every use, so it has maximum exposure for remineralizing.

    Before the jar, I used 1/2 cup of coral sand in each of 4 mason jars of RO water, and rotated them.

  12. Gregg says:

    The gentleman that commented about the minerals in water not being able to be processed by our bodies as essential minerals hit the nail on the head. You are exactly correct. In their ionic forms, 90% of minerals in water supplies from municiple water is not a form that the body will process. If you want to raise the pH of your water because your concerned about the acidity of RO water, more power to you.
    There is a reason why humans can’t live on water alone. We get our minerals and vitamins from a healthy diet. If you want to add minerals to your water and feel better about your health by doing so, great. Reverse Osmosis is an important water treatment process to thousands if not millions of people all over the world to remove impurities that may otherwise hurt us. But when there are people putting sheer conjecture and rumors on the internet about RO, they make it difficult for those that are researching options for water treatment doubt the validity of a completely legitimate and useful filtration method.
    I’ve been in the water treatment industry for over 25 years and have heard all these questions for a long time.

  13. Peter Rouvas says:

    I’ve been drinking RO water for 10 years and have never remineralized my water. It would make sense that if I was depleting my body of minerals then this would be evident in annual blood tests that I have performed which determine these levels. I have not seen any issues with blood mineral levels. I have read that a vast majority of minerals you ingest are from food and other beverages you drink, and that RO systems actually remove mostly harmful inorganic minerals…

  14. Melissa Priola says:

    Hi James, After a review of the water quality report there seems to be no issues with my water here in Charleston SC. The only issue I can think of is with the pipes that take it to my kitchen. Not only the city pipes that could have issues along the way reaching my home, but I also live in a 1940s home. I did replace the under cabinet piping in my kitchen, but not any of the rest that connects to the street. Is is safe just to get RO filter to prevent any issues in transporation to my faucet?

    Thank you!

    • Hi Melissa … I would like to see that water report. I am sure there are issues: chlorine and its byproducts for one.
      If you have a 1940s home then the pipes are old and do use lead solder.

  15. William says:

    I recently found this site where they claim to not only add minerals to their system but they magnetize the water via Loadstones. I read you comments about mineral filters begin a scam but care to comment about the “Loadstones”? They call it restructuring. ( “natural lodestones and quartz crystals to create the bio-zeta potential to charge the water and keep the minerals in a colloidal suspension. Lodestone is magnetite,”

  16. michael schieber says:

    As ” Your Filter Dr.” I can tell you the minerals are added into the water. This is proven in using water ionizers on either very soft water, or after R.O. The PH of the water and the Oxidation Reduction Potential, before and after going thru electrolysis, is greatly improved: showing the minerals are in the water. And, if in the water, will go into the body with the water.

    • Very interesting claim of being ‘your filter dr’ but I have tested the remineralizing filters and found that they do not add minerals to water. I’ll take a water test as proof over your claim to fame any day..

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