Do remineralizing filters really work? The short answer is no.
Many water treatment 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. You might see trace amounts of calcium and magnesium.
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.
The other thing to keep in mind is that minerals in water vary widely and have nothing to do with the level of minerals your body would thrive with. Just like remineralizing filters or mineral supplements have more to do with what’s in coral or what’s in seawater than what your body needs.
Do remineralizing filters really work? No, however it is true that minerals are important. In particular many people are deficient in magnesium. I supplement magnesium daily. Calcium is important but obtainable through food. We often consume too much sodium. Once again I reiterate that the water filter you need depends on what’s in your water in the first place. If you call me, we’ll look at your water report and I’ll make a recommendation on what type of treatment system to use.
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.
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.
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.
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.
I agree; also, search Magnesium Malate w Malic Acid for elimination of Al+ ions. Since 1995, Herbicide GLY was applied at Harvest to Cereals & Grains. Trace GLY kills gut Bifido- Acido-philus essential to Folic Acid Metabolism; excess Folinic or Folic Acid create Antibodies at Folate Receptors at the Blood Brain Barrier that Inhibits Folate causing Deficiency in the Cerebrospinal Fluid essential to Neurotransmitters. GLY chelates trace metals, Al+ Ions are mobilized into Brain. Confused? People with Glutin sensitivity where Folic Acid is mandated, had no issues in Italy or France.
We have been drinking R/O water for 20 years… no remineralization…. our kids grew up tall and strong and no more or less cavities than any other kid. We get our calcium from good foods we eat and other things. Also, our bodies FIGHT to be at a certain pH, so the alkaline hype is BS… I know someone who was drinking Alkaline water way before her cancer… yep got cancer. This is just marketing hype. Thank you for the article. It confirmed my BS ALERT suspicions and since I don’t have testing equipment, this was great!
Yea, you should do more research. An acidic internal environment has been linked to many diseases thanks to advances in science. Good luck to your family. I wish them the best.
You should do more research. Remineralizing filters are hype and your body has its own internal mechanisms to maintain homeostatis.
While I agree with this, please understand the process in which your body mechanisms maintain homeostasis. Populations all over the world suffer from bone density loss because of acidic drinks and not the lack of calcium intake. Rather, acidic drinks quickly result in acidic blood which the body quickly floods with calcium, salts, minerals, to urgently make the blood alkaline again. It is this vicious cycle that indeed leaches minerals from our bodies. In particular, free floating calcium in the blood must later find it’s way to settle elsewhere. Unfortunately often it results in hardening and calcification in the arteries. It is also the reason ears and noses grow as we age due to being absorbed in cartlidge. Even worse, the repeated cycle of the body flooding our blood with calcium, is the tail-chase of our body in turn flooding it with magnesium. Hence we have a silent epidemic of magnesium deficiency that causes even more inflammatory diseases to creep up over time. Be that as it may, I agree overall, that mineralization filters are largely ineffective in resolving the issue of acidic water output from RO systems. So what is the answer? We’re in a catch 22 with our disgusting water supply. (Ours is from Lake Michigan, transported and retreated locally in the Chicago Suburbs). I have been collecting my RO water in a brita filter/carafe and adding mineral drops but that proved to actually be unsafe given the dangerous trace minerals listed in the ingredients. There should be a safe, liquid additive with strictly trace minerals of calcium, magnesium, potassium, iron, etc. to safely stir into our pure RO water output.
It would be nice if there were a remineralizing filter that actually provided minerals in relation to those proportions needed by the human body. Instead all the products have a mineral content in relation to the rock structure or salt beds where they are mined.
It is actually a very big deal, you need to do more research.
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.
You may read my views on remineralization here:
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.
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.
RO filtration can be quite effective but may or may not be the best. What you need depends on what’s in your water. Learn more here.
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?
You can read more about pH (potential hydrogen) here: http://simple.wikipedia.org/wiki/PH Notice the the fact that minerals are not mentioned at all.
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.
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.
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.
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.
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.
Regarding the comments suggesting that adding a little “pink Himalayan sea salt” will add minerals back to RO water, it’s helpful to note that the mineral contribution is insignificant. To gain even the smallest benefit with that route, you’d have to consume a dangerously high level of sodium.
Under “4. Discussion” of http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7603209/ :
“Despite the many nutrients found in pink salt that are essential for health, (e.g., calcium, iron, magnesium, and potassium), an exceedingly high intake of pink salt (>30 g per day) would be required before this made any clinically significant contribution to nutrient intake”
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.
Yes, quite a hassle. When the companies that make remineralizing filters test their products they do something similar.
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.
My partner had an RO system installed in our home about three years ago. We were not informed about the issue of acidity when we made the decision to get this. I have an autoimmune disease, and had I known that I was going to be drinking water that would ruin my esophagus, we never would have gone this route. We were never told, “By the way, if you have acid reflux issues, this is probably a bad idea.” Do you discuss these issues with your customers?
“If you want to raise the pH of your water because your concerned about the acidity of RO water, more power to you.” What kind of remark is that, anyway? Do you even care that some people are being hurt by this?
First of all I do discuss the pH of RO water and 95% of the time sell a calcite filter as part of the system. This raises the pH. But I don’t think that the pH of RO water is actually dangerous or harmful. I never make medical comments as people need to speak with a trained medical professional regarding topics of that nature. As for the fellow you are responding to we’ll see if he writes back to you.
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…
Yes….the whole concept of remineralizing filters is a scam.
Using blood tests aren’t an accurate measure for mineral levels. Most blood tests do not show what the body is actually doing with those mineral levels. Many folks with autoimmune disorders have to do additional testing and find key minerals skewed even when the blood tests came back fine.
That doesn’t mean that RO water is leeching, just means that blood tests do not prove that RO water isn’t leeching. Specially when talking about membranes, such as the bowel, where the issue is supposed to be the most significant.
As to if RO leeches or not, I have no opinion.
I have used hair analysis to learn about mineral and metal levels in the body. Customers of mine have used blood tests. What do you suggest?
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?
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.
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,”
I really have no idea. IF there was any actual data to show that these do something I would love to see it.
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..
I know remineralization filters work because I have one after my RO and then attached to an ionizer. It produces molecular hydrogen because I can see it so that means there has to be mineral content in my RO water. I have attached the same ionizer to regular RO and there was no ionization that occurred.
All that means is that remineralization filters are adding something to your water. My point in saying that they do not work is that they do not offer a blend of minerals but likely only calcium and magnesium. And they certainly do not offer a plethora of minerals as described by some mfg. or anything like what the body would use in a mineral supplement. It’s a scam.
I have RO system, and I am using PH, calcite filter, made from crushed marble.
Do you think, that this kind of filters could/are leaking lead, and other unwanted toxins into the drinking water?
No I do not. The calcite used in water filters is considered safe. I’ve also tested the water from them and found no contaminants.
I applaud you for your independent research that you referenced in this topic. In an effort to validate it: could you please quantify the “Very Low” levels of TDS in the cities of Portland, Denver, San Diego etc., and what are the solids composed of? How are you defining Heart Disease? High Cholesterol leading to atherosclerosis, CHF, those with a history of angioplasty or CABG? That may help us “well” folk determine if our water sources fall in line with your theories. Keep up the good work!
There’s a link to the article on my website that discusses these studies.
I’m assessing whether a RO system would be beneficial in my case. My water tests out well under spec with exception of sodium (338 mg/L) and pH (6.3). From my understanding, the low pH is more harmful to plumbing but I am not too concerned as are home uses PEZ water lines.
My main concern is the sodium levels from both a health and taste standpoint. Would an point of use system make sense in my case?
You definitely need reverse osmosis to remove the sodium. and you need a calcite filter to raise the pH throughout the house.
Pex pipe leaches chemicals.
What do you think about “restructuring” the water after it is purified?
I think it’s interesting and there may be some subtle benefit. It didn’t improve the look of my plants.
We use the remin vitev filter. Have you come across it at all? It would be interesting to see if it’s just as ineffective in re-mineralizing the water.
I can’t say, but it uses the same materials as the ones I’ve tested that didn’t do as claimed.
more than 90% of all bottled water being sold in the stores is processed by Reverse Osmosis and millions of people have been drinking it everyday for years and they do not even realize it. They do sell some brands that offer electrolytes or minerals added but most are just plain R.O. If R.O. is so bad then why are not more people collapsing with heart attacks and brittle bones ? I have read thousands of articles dealing with R.O. and there are so many different opinions on the safety and benefits or hazards it is ridiculous to try and figure out the truth. After researching the people behind most of the articles I usually discover they are selling some type of water filters which they think is better than all of the others or they are trying to sell books or information. It makes it very difficult to find the truth .
I think that’s right. RO water is fine. It is more aggressive and I would avoid bottled water that’s been sitting in heat or the sun. It is likely leaching plastic or phthalates from the plastic bottle. I personally avoid RO water in bottles. Mineralizing filters don’t add the minerals they claim to. The brands that add minerals are doing so but I don’t like the taste.
I am a complete novice in the water quality field. I have only recently started researching/getting into water quality after reading my water districts water quality report for the first time and seeing how many contaminates my family and I drink on a daily basis.
Specifically concerning remineralization filters, I reached out to a company (prior to finding your blog) regarding their remineralization filter. I wanted to know if they had any data on how much this filter increases pH, as well as the amount of each mineral added. Per their website the filter would increase natural minerals (calcium, magnesium, and copper being among the things added back to water)
Per customer support:
The filter would add around 1PH to current tap’s PH and at lease 10 ppm of each of the minerals mentioned.
Can the second answer “at least 10ppm” be true?
Per my Water Quality Report the “Regulatory Action Level (The concentration of a contaminant which, if exceeded, triggers treatment or other requirements which the water system must follow)” for copper is 1.3ppb. If this filter added 10ppm of copper, then my RO filtered water would now be adding over 7,500 times the limit allowed by my municipal water supply.
Like I said, I am completely new to this field. Am I interpreting this information correctly? Am I missing something? I suspect that the answer I received from customer support is incorrect.
Thanks so much for your time and all the information you provide to the community.
In my experience the amount of pH increase is unpredictable and varies with water source and temperature.
As for their estimate of mineral input I would doubt the accuracy of that as well.
With the calcite filter I use I see maybe 3 + ppm of calcium, 1 + ppm of magnesium, and an unpredictable pH increase.
Water ionizers will not work properly nor produce molecular hydrogen if the water is void of minerals.
The primary minerals, Sodium, Potassium, Calcium, and Magnesium are your electrolytes if I’m
mistaken. Alkaline water is far better for good health than Acidic water.
I think that highly alkaline water, pH over 8. 5, is dangerous. And that alkaline ionizers are completely unnecessary. I would agree that slightly alkaline water, ideally a pH of 7.4, is typical in nature. Though of course water comes in many variations. I don’t really see any problem with acidic water since the water you drink is entering the stomach which is already acidic. The whole topic is misconstrued. The body is perfectly capable of maintaining its own pH regardless of the water you drink. Now soft drinks, acid and sugar, those are unhealthy.
I am afraid that I cannot agree with you. I know numerous natural health doctors who recommend distilled or RO water to remove everything. The purpose of water is to hydrate the body, not to provide minerals.
Regarding my own experience having reviewed hundreds of water reports every water supply is different and none have this WHO idea of 20 mg/l magnesium and 40 mg/l calcium. Review some water reports and you’ll see.
I have checked and analyzed and drawn my own conclusions. You certainly can supplement minerals. And removal of the contaminants present in US water supplies far outweigh any benefit from minerals.
I am grateful for your blog since I became aware of the widely reported dangers of drinking and cooking with demineralized water. Until recently, when I added a calcite filter, I was using my RO without remineralization as the primary water source for my three dogs, two of whom have since died of apparent old age. I keep feeling guilty that their only source of fluid was essentially demineralized water with a ph of 6.8. Do you have any sources I can read that debunk the findings from multiple studies that insist that drinking demineralized water is detrimental to human and animal health due to its disruption to homeostasis? I am feeling very guilty that I didn’t take better care of my pets.
There are not numerous studies on this topic. There is one World Health Organization study and it is flawed. See the article I wrote here.
While minerals may not provide a large portion of trace minerals for most people, they do provide some of the recommended intake and it’s enough to be “clinically significant” (see link below). That should not be dismissed. Your body absolutely can absorb minerals from water.
Separate from mineral absorption, there may be negative effects from drinking water without minerals for reasons other than mineral intake:
That says “demineralised water increased diuresis and the elimination of electrolytes, with decreased serum potassium concentration”, among other things. The loss of electrolytes could be from equalizing what is in your body with the pure water you drink.
Lastly, you say remineralization doesn’t provide trace minerals, but it absolutely does. You say it yourself later, that it adds calcium and magnesium. Maybe it doesn’t add a wide range of trace minerals, but it does add those and so it’s dishonest to say it adds none and is a completely scam. The positive effect on pH is enough for it not to be a scam. Of course some remineralization is indeed a scam, like the Livation garbage that has magic ceramic beads and magnets, but a calcite filter is useful for calcium, magnesium, and pH.
Let me say it again: remineralizing filters are a scam. There.
If you actually study the mineral content of water it has nothing to do with human health. For instance in San Fracisco, Seattle, and New York mineral content is extremely low with a wintertime number of perhaps 45 ppm. This is because these water sources are from rain and snow and haven’t had time to dissolve additional minerals from interactions with soil or rock. Yet there is no evidence that this low level of minerals causes negative health effects in these cities.
On the other hand mineral content in Southern California water ranges from 500 – 650 ppm, with one of the sources being the Colorado River and it having run through the sandstone of the Colorado Plateau. This level of minerals is far too high. The higher the mineral content of the water the less hydrating it is.
In fact neither of these extremes is optimal for human health. The article you quote cites the following:
“Recommendations for magnesium have been put at a minimum of 10 mg/L with 20–30 mg/L optimum; for calcium a 20 mg/L minimum and a 40–80 mg/L optimum, and a total water hardness (adding magnesium and calcium) of 2–4 mmol/L. At water hardness above 5 mmol/L, higher incidence of gallstones, kidney stones, urinary stones, arthrosis, and arthropathies have been observed.”
There is unlikely to be any water source in the US that provides this combination of minerals.
The calcite filter I use on my RO produces about 3 ppm of calcium and 1 ppm of magnesium after the RO has rid the water of whatever minerals it contained. I use the calcite filter to raise the pH of the water and to mimic, to some extent, natural sources. I’ve researched the other mineralizing filters, such as magnesium oxide or coral calcium and they raise the pH to extreme, too high in my opinion. And they don’t add any more minerals than the calcite filter. While there are over 70 trace minerals in coral calcium they do not get dissolved by the RO water as it passes through the filter at 1 gallon per minute.
As for pH most natural water sources would be a pH above 7. RO water will have a low pH below 7. Your stomach is acidic, having a pH of 2. (https://www.sciencedirect.com/topics/biochemistry-genetics-and-molecular-biology/stomach-ph). So I don’t think it really matters what the pH of the drinking water is as the first place it goes is your stomach. In my opinion high pH water may negatively affect your health over time.
Please note finally that the Wikipedia article you are citing lacks citations. The issue is actually relatively complex and is subject to extensive misinformation promoted by people who have no idea what they are talking about.