People have strong opinions about drinking water.People have strong opinions about drinking water.
TL;DR
Demineralised drinking water does not suddenly strip minerals from your body. Most essential minerals come from food, and your body carefully regulates them.
However, calcium and magnesium in drinking water can still support nutrition, improve taste and reduce pipe corrosion. Completely purified water may be helpful when serious contaminants are present, but it is not always necessary.
The best drinking water is not simply the water with the lowest mineral reading. It should be clean, safe, pleasant to drink and suited to your local water supply.
Some say only completely purified water is safe. Others say mineral-free water strips nutrients from your body.
Both claims go too far.
Clean drinking water matters. Minerals also matter. But the real story is more balanced than either side suggests.
Let’s look at what demineralised water is, what it does, and what the evidence says.
What is demineralised drinking water?
Natural drinking water usually contains dissolved minerals.
These may include calcium, magnesium, potassium, sodium and bicarbonate. The amount varies between water supplies.
Hard water contains more calcium and magnesium. Soft water usually contains less.
Demineralised drinking water has had most of these dissolved minerals removed. Reverse osmosis, distillation and deionisation can all produce low-mineral water.
These systems may also remove many unwanted substances. Depending on the system, these can include lead, arsenic, fluoride, nitrate and PFAS.
That sounds good. But removing almost everything creates a new question.
Do we really want drinking water containing almost nothing?
Does purified water steal minerals from your body?
You may have heard that distilled or reverse-osmosis water is “hungry water.”
The claim is that mineral-free drinking water enters your body and steals calcium, magnesium and other nutrients.
That description is misleading.
Your digestive system is not a metal pipe. Water does not simply wash through your body, grabbing minerals along the way.
Your kidneys, intestines and hormones constantly regulate water and electrolytes. They retain what the body needs and remove what it does not.
There is no convincing evidence that an ordinary glass of demineralised drinking water suddenly strips useful minerals from healthy tissues.
Drinking too much of any water within a short period can dilute blood sodium. This is called water intoxication. However, it can happen with tap water, filtered water or distilled water.
The main danger is excessive volume—not the lack of minerals.
Most minerals come from food
Our bodies need calcium and magnesium.
Calcium supports bones, teeth, muscles and nerve function. Magnesium helps with energy production, muscle contraction and hundreds of enzyme reactions.
However, food usually provides most of these minerals.
Calcium comes from dairy foods, sardines, leafy vegetables and other foods. Magnesium occurs in meat, seafood, nuts, seeds and vegetables.
Drinking water normally provides a smaller part of our daily intake.
The amount can still be meaningful, especially in hard-water areas. But water is not normally our primary food source.
If your diet supplies enough minerals, drinking low-mineral water occasionally is unlikely to create a deficiency.
That does not mean minerals in drinking water are worthless. It means we should keep their contribution in perspective.
Minerals in drinking water can still help
Calcium and magnesium dissolved in drinking water are available for the body to absorb.
In some areas, drinking water ccan provide a useful addition to dietary intake. This may matter more for people with limited diets or low mineral consumption.
The World Health Organization examined the possible health effects of long-term consumption of manufactured, desalinated and demineralised water.
Its expert report did not simply declare mineral-free drinking water poisonous. It examined whether removing calcium and magnesium could reduce a useful source of nutrition.
The report concluded that mineral content deserves consideration when purified water becomes a population’s main supply. This is why large desalination plants commonly add minerals back before distribution.
Remineralisation also improves taste and makes water less corrosive.
That is quite different from saying one glass of distilled water will rob your bones.
Why mineral-free water tastes different
Minerals help give drinking water its familiar taste.
Water containing moderate amounts of calcium, magnesium and bicarbonate often tastes fresh and satisfying.
Completely demineralised water may taste flat, empty or slightly sharp. Some people like it. Many do not.
Taste matters because people drink more water when they enjoy it.
A purification (for instance reverse osmosis) system may remove contaminants brilliantly. But if nobody likes the resulting drinking water, the system has failed in another way.
Good drinking water should be safe, pleasant and practical enough to use every day.
Low-mineral water can affect plumbing
Demineralised drinking water behaves differently inside pipes and storage tanks.
Water with very few dissolved minerals can be more corrosive. It may absorb metals and other substances from materials it contacts. This is very obvious in areas like Victoia where lead from ols plumbing has been ‘pulled’ from pipes by relatively ‘soft’ water.
This does not mean purified water attacks your body. It means low-mineral water may interact more aggressively with plumbing.
Poor-quality pipes, fittings, tanks or taps could release lead, copper or other materials into the water.
Large water-treatment plants carefully control pH, mineral balance and corrosion. A household system also needs suitable materials and proper installation.
There is little value in producing pure drinking water and then contaminating it during storage.
What happens when you cook with it?
Water naturally draws soluble substances from food during cooking.
This happens with tap water as well as demineralised drinking water. It is one reason vegetables can lose minerals and vitamins when they are boiled.
If you discard the cooking water, you also discard whatever moved into it.
Soup is different because you consume the water with the food. Most of the dissolved nutrients remain in the meal.
Claims that demineralised drinking water always destroys the nutritional value of food are exaggerated. Cooking time, temperature and whether the water is discarded all matter.
Steaming vegetables can reduce nutrient loss. Using less water can also help.
Is reverse-osmosis water dangerous?
Properly produced reverse-osmosis water is not inherently dangerous.
Millions of people drink it. Reverse osmosis can be extremely useful where water contains salt, nitrate, fluoride, arsenic or other difficult contaminants.
It may be the correct treatment for a particular water problem.
However, reverse osmosis removes beneficial minerals along with unwanted substances. It also produces wastewater and usually requires a storage tank.
Some systems add calcium and magnesium back afterwards. This can improve taste and reduce corrosiveness.
The better question is not, “Is reverse osmosis bad?”
The better question is, “Does my water actually require reverse osmosis?”
A good water test should guide that decision.
Not every dissolved substance is a contaminant
People often use “mineral” and “contaminant” as though they mean the same thing.
They do not.
Calcium and magnesium are minerals. Lead and arsenic are also naturally occurring elements, but we do not want them in our drinking water.
Chlorine can protect public water from dangerous bacteria. Yet many people prefer to remove it before drinking.
PFAS are not useful minerals. They are persistent industrial chemicals.
The goal should not necessarily be to remove absolutely everything. It should be to reduce unwanted substances while producing safe, enjoyable drinking water.
Selective filtration can often achieve this without stripping the water completely.
What makes good drinking water?
There is no single perfect mineral level for everyone.
The right system depends on your water source, local contaminants, plumbing and personal needs.
Good drinking water should:
- Be microbiologically safe.
- Contain no dangerous level of contaminants.
- Taste pleasant.
- Work safely with household plumbing.
- Support regular hydration.
- Be produced without unnecessary waste.
- Retain or restore an appropriate mineral balance.
People using rainwater, bore water and town water may require very different treatments.
Testing should come before buying.
The Sensible Conclusion
Demineralised drinking water will not suddenly suck minerals from your body.
That claim makes a complicated subject sound frighteningly simple.
However, it would also be wrong to say minerals in drinking water never matter.
Calcium and magnesium can contribute to nutrition. They improve taste and help make water less corrosive. Their contribution may be especially valuable when someone’s diet is already low in minerals.
Completely purified drinking water can be appropriate in certain situations. Remineralisation may make it more suitable for long-term everyday use.
For many Australian homes, selective filtration offers another approach. It can target unwanted contaminants without removing every naturally occurring mineral.
The best drinking water is not necessarily the water with the lowest possible reading on a TDS meter.
It is water that is clean, safe, pleasant and suited to the people drinking it.
That is a much better goal than chasing “perfect purity.”
