It is unfortunate there is so much miss-information about RDD treatment.  Reverse osmosis and distillation are very effective water treatment methods, and are often the best water treatment options when the source water contains harmful mineral ions and salts – contaminants that are not easily removed by activated carbon filtration.

The origin of the current "distilled water is harmful" claim can be traced to just two sources, near as I can determine.

Nearly everyone who reaches this site will have read a paper by Zoltan P. Rona with the alarming title "Early Death Comes With Regular Drinking Of Distilled Water". 

This paper has been quoted or published in books and on hundreds of web pages (usually with the original title "Early Death Comes From Drinking Distilled Water").  While Dr. Rona cites some anecdotal evidence from his practice, he provides no experimental evidence or references to good studies that would support various statements in the paper.

Other statements in Dr. Rona's paper also reveal what appear to be fundamental misunderstandings of how the body regulates inter/intra-cellular pH and the differences between soft water (water lacking calcium, magnesium and other “hardness minerals”) and distilled water (water lacking all minerals and other contaminants).  I finally wrote to Dr. Rona (spring 2009) requesting some evidence to back up his statements.  He did not responded to the initial request or a follow-up e-mail several weeks later.  However shortly after I wrote him, the title of his paper was changed.  My questions to Dr. Rona can be found here.  Perhaps if enough people contact him requesting evidence for his statements he will provide some to somebody!  His e-mail address is here.

The other primary source of the "Distilled Water is Harmful" myth is chapter 12 of a report, Nutrients in drinking water, published by the World Health Organization (WHO).  A good rebuttal to the article was published by the Canadian Water Quality Association, and I discuss some other aspects of the paper here.

One of the websites where Dr. Rona's paper has been republished along with an editorial, "Why I Now Say No to Distilled Water Only"  is chetday.com.  Those articles are currently listed on the first page of a Google search on "Distilled Water and Health".  I recently wrote to chetday.com asking if they had any additional evidence to support the claims about harm from drinking distilled water.  It tuned out that the article was prompted by experiences with a vegan group that drank only distilled water.  "Essentially, our opinion and experience is that anyone following a strict vegan – especially primarily RAW foods – diet longterm should not be drinking distilled or R/O or D/I water, but, as said above, that water is most likely the smallest thing to worry about due to other deficiencies." And on another occasion "Honestly, hard-line vegan diets are so terribly deficient in protein, B-12, calcium, and a host of other nutrients that distilled water ingestion I suspect would be the least of their worries, though it absolutely would not be helping them and certainly would be contributing to deficiencies (in my opinion at at least)." (Josh Day).  An article I wrote, Drinking Water: Facts, Scams, and Treatment Methods, was published on chetday.com.

It is interesting that those who promote the idea that "water without ions is bad" are typically the groups that sell filters which do not remove beneficial minerals like calcium, magnesium, phosphorus, etc. from the water.

Those who claim that "RDD water is beneficial" ("and actually better than drinking water that contains minerals") are – no surprise – the ones who sell RDD systems.

Many "health-related sites" fall in between – if one of their diets or cleanses requires some sort of body "purification" they will often suggest drinking RDD processed water to help leach harmful contaminants out of the body (see argument 2 below).  

Obviously, the discussion below will focus only on the presence or absence of the "good/beneficial" ions (like calcium, magnesium, and potassium) that are removed by RDD processes.  It is a given that it is good to remove all harmful ions like lead, mercury, etc. (as well as other harmful contaminants) by RDD or by any other process.

There are four threads to the "RDD water is harmful to health" argument:  
1) Essential minerals are removed from the water – and that's bad.
2) Demineralized water 'leaches' minerals from your body – and that's bad.
3) Distilled water is more acidic than regular water and that's bad.
4) Distilled water is dead (or has lost its vital force) and that's bad.

Response 1: It is true that RDD removes the "good" minerals along with the harmful contaminants, but it is by no means true that drinking water is the only source (or even the primary source) of these minerals.  The recommended daily requirements for calcium and magnesium are about 1,000 - 1,200 mg and 300 - 400 mg respectively (with specific requirements that vary by age, gender, etc.).

According to one table the hardness scale provides information about the amount of calcium in various degrees of hard water.

According to the table above, water that is slightly to moderately hard will contain up to about 50 mg/l of calcium.   Reports I have seen indicate that magnesium levels average about 12 - 15% of the calcium levels (or about 7.5 mg/l).  One liter (about 1 quart or four 8-oz drinks) of hard to very hard water will contain around 72 mg/l of calcium and perhaps 11 mg/l of magnesium.  Extremely hard water, though, can contain over 1,000 mg/l calcium carbonate (CaCO₃₎, or over 400 mg of calcium 

So, drinking eight {8} glasses (about 2 liters) of slightly to hard water a day will provide your body with about 14 - 144 mg of calcium. That translates to a maximum of about 1.2% to 12% of the daily 1,000 to 1,200 mg of calcium your body requires. In that same 8 glasses of water you will be supplying your body with about the same percentage of your daily requirement of magnesium.  One glass of milk, by comparison, contains about 300 - 350 mg of calcium – over twice as much as 8 glasses of hard water. 

Hard water that contains calcium and magnesium can realistically be a source of up to about 15% of your daily requirements for these minerals. It is reasonable to assume that non-RDD water would provide similar proportions of trace minerals.  However, your body does not care where the minerals come from, drinking water, diet, or supplement**.  So, as long as you get enough calcium and magnesium (and other essential minerals) from some source, there should be no health problems for most people even if they drink RDD processed water and obtain none of their essential minerals from that source.  If a person's diet is so bad that they must depend on drinking water to meet the minimum daily requirements of certain minerals, they will probably be severely malnourished and have a variety of medical problems.

**There is a qualification to the statement above.  While the body does not care where the minerals ultimately come from – that is, calcium from water, milk, diet, or from supplements is used by the body the same as calcium obtained from water – the bioavailability of calcium (or other minerals) is affected by the form in which the calcium is delivered to the body.  Calcium citrate, for example has been shown to be 2.5 times more bioavailable (easier for your body to use) than calcium carbonate.  Some articles attribute that difference in absorption to the fact that organic forms of calcium (citrate, lactate, etc.) dissolve more easily in the stomach – releasing the calcium ions – than calcium carbonate (which is where much of the calcium in water comes from and which you might find in an inexpensive supplement).  Other studies I have read indicate there is little difference.  It must be noted, however,  that the calcium in water is already dissolved.  I have not read the result of studies where the absorption of dissolved types of calcium supplements are compared, but I suspect that the bioavailability of any calcium ion that arrives in the stomach already dissolved may be similar.

There are substances that interfere with the body's ability to absorb and use calcium including oxalate, protein, phytate sodium and caffeine, and vitamin D is essential for the absorption and use of calcium.

Another point I read is that cooking in water that is low in minerals (RDD water) will extract more minerals from food than cooking with normal water thus lowering the amount of minerals in the diet.  This sounds like a reasonable critique of RDD water, however I have not read results of actual experiments that measured and compared the calcium and other mineral levels in food prepared with normal and RDD water.

A warning: Do NOT believe the hype you may read about coral calcium providing any advantages over other sources of calcium, either in the diet or in supplements.  Coral calcium is simply calcium carbonate.  It is, however, unregulated and unpurified and (like calcium supplements from oyster shell, dolomite, and bone meal) may contain harmful levels of heavy metals like lead and mercury.  This type of scam is similar to the altered water scams discussed elsewhere on my site in that they are very expensive, and all evidence about the benefits of these products is self-generated and not supported by any legitimate scientific studies.  They differ in that the altered water scams are typically harmful only to your pocket book, while these unregulated supplements can be harmful to your health as well as your pocket book.

**That said, there is a body of evidence that is hard to ignore that points to reported health benefits from drinking hard water instead of soft water. As several of the articles below point out, however, there is no consensus about the actual cause of the findings (it may be something in the soft water that is harmful rather than the calcium and magnesium ions in the hard water that are beneficial, for example) or even how real the effect is.

RDD water will also have all fluoride removed (natural and/or added).  Depending on your stance on the benefits or harm from fluoride in your drinking water (a whole different discussion that is far more contentious than the RDD/non-RDD issue), that may be an issue. In some locations, drinking water is a major source of fluoride. So, if you are a believer in the benefits of fluoride in drinking water, you may wish to make certain you and your family obtain enough of that chemical from other sources.

The National Academy of Sciences and the National Osteoporosis Foundation
Hard Water Hardness Calcium Magnesium Water Corrosion Mineral Scale
Linus Pauling Institute - Micronutrient Information Center - Calcium
Drinking Water and Health, Volume 1
Calcium Citrate vs. Calcium Carbonate
Coral Calcium – The answer to how do you spell HYPE?
Calcium Info - Supplements
Calcium - Encyclopedia of Alternative Medicine
The "Mother" of all magnesium and health sites:
  Several representative articles
  Magnesium and calcium in drinking water and cardiovascular mortality
  Calcium and magnesium in drinking water and risk of death from cerebrovascular disease.
  Minimum Magnesium Standard for Drinking and Bottled Water Would Save 150,000 Lives Annually

Response 2: If you are talking about pipes and storage containers, RDD water could be considered more "aggressive" than water containing dissolved substances.  Water without anything in it will tend to dissolve anything it comes in contact with (the copper or iron in a pipe, the lead from a solder joint or brass fixture, etc.) more 'aggressively' than water that already contains some dissolved substances. Also, one of the "things" easily dissolved by RDD water is carbon dioxide. This forms a weak acidic solution (carbonic acid) which can cause further dissolving and corrosion of materials that it comes in contact with – that's how caves get formed – soft, acidic rain water dissolves limestone (calcium carbonate) and becomes hard water in the process of forming the cave structure.  I have found no evidence, though, that RDD water dissolves significently more CO₂ than regular water.

The above is a valid argument for only storing RDD water (or any water) in clean glass containers which are chemically inert.

Now, does this "aggressiveness" of RDD processed water translate to actually leaching minerals out of the human body? I have looked regularly in the scientific literature for good evidence of this alleged phenomenon without success. I have not been able to find anything in the literature specifically about long term effects of drinking RDD water on health – the only articles I can find are about he health effects of soft water and lead back to the hard vs. soft water health benefits discussed above.  I use the word 'contaminated' below to describe anything besides pure water.

	Ideally RDD water contains nothing except perhaps some dissolved CO2 picked up from the air.
	Adding anything to that pure water will 'contaminate' it.
	The alleged leaching of minerals from the body is said to take place in the small intestines because of the "pure, aggressive" water that comes in contact with the intestine lining – as opposed to hard water with a few milligrams of calcium or other ions which is claimed will not cause this leaching of minerals.
	Consider the contents of your stomach, particularly after a meal – a huge mix of every conceivable type of organic and inorganic compound plus a healthy dose of hydrochloric acid.
	It does not matter where pure water becomes 'contaminated' (in the ground, in the distribution system, on the kitchen counter, in your body) – adding anything (from any source) to water will 'contaminate' it.
	Imagine two glasses of water on the counter – one containing clean, filtered tap water with a few milligrams of calcium and magnesium, and the other glass containing only pure, RDD processed water with no ions.
	Imagine now the difference a few milligrams of ions will make when either glass of water hits the contents of your stomach! Since any alleged harmful effect of drinking RDD water does not happen until several hours later when molecules from the glass of water eventually reache your intestines, it is very difficult to believe that the presence or absence of a few ions in the original water will make any difference at all.

Another way to look at it: Since it does not matter to the body where water becomes 'contaminated' (externally or in your stomach), consider this "thought experiment":

	Take a blender, throw in a cheeseburger meal with all the trimmings (fries, pickle, and a shake)** , turn the blender on and mix the together thoroughly.
	Fill two glasses of water 1/2 full, one with pure RDD water, with no ions,  and one 'contaminated' with calcium and magnesium ions.
	Pour 1/2 of the burger mixture into each glass of water and mix.
	Now, which is the more 'contaminated' glass of water – is it really going to matter to your body which glass of water you drink – the glass of water that started with perhaps 2 - 18 mg of calcium ions or the glass of "pure" water that started with 0 mg.
	Drink the mixtures – Yuck!

** Using the nutrition guide at Colorado State University Cooperative Extension and adding together the calcium, sodium, and potassium levels of a hamburger patty, 1/2 oz cheese, bread, tomato slice, 20 chips, and a pickle, I found the total ion content of those three cations to be roughly 3,192 mg (nearly 3.2 grams).  That is several hundred times more than might be in the non-RDD water.  Calcium levels would be around 178 mg, Sodium  around  1,740 mg, and Potassium about 1,274 mg.  And, that's the concentration of just 3 ions.  All of the other 'contaminants' (other ions, carbohydrates, fats, and proteins, etc.) would make the initial difference between the RDD water and the filtered water even more insignificant.  Calculate your calcium intake with the online Calcium Calculator from the BC Dairy Foundation.

Since water from reverse osmosis and distillation systems are about two and four times more expensive respectively than good filtered water, the only negative impact I can see to these methods of treatment for most people is to the pocket book. 

Another fact to consider – probably over 50% of the water you take into your body throughout the day is very heavily contaminated. Think of drinking coffee, tea, juice, smoothies, wine, beer, etc.  These beverages contain a very complex mix of organic and inorganic chemicals.  Even "solid" food contains significant amounts of water – cooked meat, for example, contains over 50% water.  Most people do not consider their dinner to be contaminated water, but technically it is.  The point – compared to most of the water that enters your body containing grams of salts and minerals, the debate over the few milligrams of calcium and magnesium that are in non RDD water and missing in the pure RDD water seems rather pointless.

**Several visitors have commented that drinking too much RDD water can lead to ion imbalances in the body which can cause serious health problems.  This is true, but so can drinking too much regular water.  The condition is known as water intoxication.  The discussion above assumes that people are eating regularly, getting enough minerals in the diet and supplements, and not drinking an excess of any type of water.

If, however, your water contains contaminants, like nitrates or heavy metals that are not removed by a specific filtration system, then reverse osmosis and distillation treatment methods are a good options (often the most economical option) for producing clean, safe water for drinking and cooking.

References about digestion and absorption:

Absorption of Water and Electrolytes
The small intestine must absorb massive quantities of water. A normal person or animal of similar size takes in roughly 1 to 2 liters of dietary fluid every day. On top of that, another 6 to 7 liters of fluid is received by the small intestine daily as secretions from salivary glands, stomach, pancreas, liver and the small intestine itself.
By the time the ingesta enters the large intestine, approximately 80% of this fluid has been absorbed. Net movement of water across cell membranes always occurs by osmosis, and the fundamental concept needed to understand absorption in the small gut is that there is a tight coupling between water and solute absorption. Another way of saying this is that absorption of water is absolutely dependent on absorption of solutes, particularly sodium:

Water
An important function of both small intestine and colon is the absorption of water and electrolytes. Approximately 2000 ml of food and drink is ingested daily, and the volume of gastrointestinal secretions (salivary, gastric, biliary, pancreatic and intestinal) is about 8,000 ml daily; therefore, approximately 10 liters of fluid enters the intestine each day. Of the 8 liters secreted, about 1 - 1.5 liters enter as saliva, 2 - 3 liters are secreted by the stomach, about 2 liters enter as bile and pancreatic secretion (about 1 liter each), and about 2 liters are secreted by the small intestine.  (Please note that these figures are approximate, not absolute.

Volumes may vary, depending on experimental method and conditions.) Of the 10 liters which enters the gut each day, only about 1 liter passes into the colon, about 90% having been absorbed across the small intestinal epithelium. Only about 150 ml is lost in the feces daily, with the remainder being absorbed by the colon. It should be obvious that any derangement in intestinal fluid absorption would profoundly influence the balance of fluid and electrolytes in the body, and that the normal functioning of the intestines plays a significant role in regulating water and electrolyte balance. The net absorption or net secretion of water in the intestine is the result of bidirectional movements of water from mucosa to serosa (m–>s flux or absorption) and from serosa to mucosa (s–>m flux or secretion). In the human intestine, these unidirectional fluxes exceed net movement 2 -3 fold.  The rate and direction of net fluid movement depend on tonicity of the meal, and move toward the achievement of isotonicity {equal concentration of water on both sides of a membrane - RJ}. 

The intestinal mucosal surface consists of a bimolecular lipid membrane, which (presumably) contains small pores or channels. Water and water-soluble substances can hypothetically enter the cell through these pores only, while lipid-soluble substrates can directly cross the lipid cell membrane. Specialized protein pores, referred to as aquaporins (AQP) have been identified in many tissues, including colon epithelium; water channel isoforms in small intestinal epithelium remain to be discovered. Intestinal absorption of water is a passive process and requires movement of solutes. Water accompanies solute and moves across the intestinal mucosa in response to osmotic gradients. The rate of water uptake in any region of the intestine is a function of solute absorption in this region. All areas of the intestines (including small bowel and colon) absorb water, the relative amounts absorbed depending on the presence of solutes {things dissolved in water, sodium, calcium, sugar, etc. - RJ}, and the types of solutes present. In the jejunum, the active transport of sugars and amino acids causes passive movement of salt and water, which accounts for most of the water uptake in this area. In the ileum, most water movement is accounted for by active sodium transport.

As described in Johnson (Gastrointestinal Physiology), coupled water and sodium transport involves a specialized mechanism that pumps sodium into the lateral spaces, resulting in relatively high osmotic pressure in that region. Water then enters the lateral space from the cell (transcellular flux) and–perhaps–the lumen (paracellular flux), reducing the osmotic pressure but increasing the hydrostatic pressure. Fluid is then forced out of the lateral space into the interstitial space. The net effect is that isotonic fluid is transported from the lumen into the extracellular fluid. This hypothesis of fluid absorption is illustrated in Figure 12-5, on page 137 of the Johnson resource.

Response 3:  Basically this is a bogus marking claim made by those who market alkaline (ionized) water products.  Any water can absorb carbon dioxide from the atmosphere and become somewhat acidic.  This insignificant acidity has no effect whatever on health.  Read the detailed answer about alkaline water here.

Response 4: As noted above, distilled water is not "dead" nor has it lost its "vital force". These ideas are scientifically and philosophically meaningless. All water molecules, whether from a distiller, a water tap, a rain cloud, or a pristine natural spring are exactly the same physically, chemically and energetically.  Water molecules are not alive by any definition of life one cares to use.  Nor do water molecules embody some special, undefined "vital force".  And, despite Emoto's pretty pictures of ice crystals, water is not capable of modifying its behavior in response to human thoughts, words or music.  Water is a simple inorganic molecule made up of one atom of oxygen and two atoms of hydrogen.

Drinking 4 to 6 eight glasses of distilled water a day should not cause a health problem – relative to drinking the same quantity of non-distilled water.  The two types of water are not different – certainly not in the chemical and physical behavior of the water molecules.

Your story is very compelling, but with a sample size of one, and no control, there is no way to know what the actual cause was of your recovery, although the timing was certainly suggestive.  The evidence would have been more compelling if, instead of simply switching to non-distilled water you had someone “blind” the water you drank.  For example, for a week or two you would only drink either the distilled or regular water (but not know which it was) and record how you felt.  After a period of time you would get the other type of water to drink for a couple of weeks (again, not knowing whether it was distilled or regular) while maintaining your health record.  After the trial period you would give your notes to another person (not the one who blinded the water) who would summarize any health differences you recorded for the two periods during which you were drinking the distilled or non-distilled water.  That kind of blinded experiment, performed on dozens to thousands of individuals (randomized into different treatment or control groups), is the basis for much of what we understand about the workings of nature.  Blinding and randomization are two tools that help minimize the effects that emotional involvement, judgment calls, bias (intentional or unintentional), expectations (power of suggestion), spontaneous remissions, and so forth can have on the results of experiments if the investigators and/or the experimental subjects are aware how the treatments are being administered and what the "expected" outcome is..

I simply have not found any published experiments that document a difference in health between drinking distilled vs. “regular” water although I keep looking.

I have heard of "Dr." Masaru Emoto, and completely skeptical of his work.  It is unlikely, for instance, that beautiful ice crystals would ever grow in distilled water because the crystals need a nucleation point – an impurity in the water or defect on the slide – on which the crystal can begin to grow.  The purer the water, the less likely a beautiful crystal would form.  He has, to the best of my information, published no papers detailing results of blinded experiments in any reputable scientific journal, and his work is not recognized by the scientific community.  There is a quote on this site from world's foremost snowflake researcher and photographer, Kenneth G. Libbrecht of Caltech. In addition to providing some extraordinary photographs of water crystals he completely dismisses the work of Masaru Emoto. You can read my additional comments and a review and analysis of Dr. Masaru Emoto’s published work on the effects of external stimuli on the structural formation of ice crystals.

I have looked for studies on health effects of distilled water going back to the early 70s at pubmed – the principle search engine for articles published in medical-related journals.  I used different search terms: distilled water health (112 articles), drinking water distilled (391 articles), and water absorption distilled (562 articles).  demineralized water health (16 articles) Unfortunately, none of the more than 1,000 articles that had distilled water in their title or abstract dealt with health effects of distilled water.  Similarly, restricting the Google search on "distilled water and health"  to .edu sites (one way to 'weed out" a lot of the bias on the web) also yielded no answers.

It would have been a bit more helpful to the discussion if you had tried to either treat your dog with a change in water or diet separately instead of at the same time, but hindsight is always a better predictor of outcome than foresight.  If you had just changed the type of water your dog drank and then noticed that the symptoms were better, that would have been an interesting observation in favor of drinking low-mineral water – for that condition.  However, as I point out elsewhere, results from an experiment with a sample size of 1, while interesting, do not demonstrate that a hypothesis (theory) is true or false.

If elevated calcium levels and parathyroid growth was a fairly common problem in dogs and the Vet was willing to do some experimentation, he could set up some blinded trials – treating one group with distilled water and another group with purified water (neither the Vet nor the owners would know which treatment the dogs were given).  If statistically significant differences were found between the two groups that would indeed demonstrate that distilled water might have some health effect.

Best wishes.