Distilled water is well proven way to get clean and drinkable water.
But it isn’t totally beneficial for the body.
There’s a significant carbon cost so it’s bad for the environment.
And it doesn't remove all contaminants from the water
How it works
Distillation is a process used since ancient times.
Put simply; distilling is where you boil water in one container and catch the steam.
Then it condenses back into water which you catch in a second container - leaving the contaminants behind in the first container.
The boiling process itself kills bacteria, viruses, and parasites.
It’s generally a useful, well tried and tested way to purify water.
But Distilling Water Doesn't Remove all Contaminants
The reason for this is that any chemicals / volatile and semi-volatile organic compounds (VOCs) that have a boiling point around or below water are not removed.
They will simply be carried along in the steam and end up in the second “purified” container.
Examples of these chemicals are; some pesticides, benzene, toluene, chlorine, chlorine by products and other VOCs.
This is Distillation’s crucial disadvantage to Reverse Osmosis - which is usually the main rival to distillation methods.
Because of this, plus the high energy cost of distillation, Reverse Osmosis is much more popular in domestic settings.
The failure to remove chlorine is a marked one. Chlorine is the top contaminant in most municipal / mains water supplies.
It's great for bringing cleaner water to your tap. But ideally you don't want to actually drink it.
So while distillation might work well in certain settings - like large scale seawater desalination plants, or certain "off-grid" situations - its basic failure to remove chlorine means it's makes it very questionable for domestic use with mains water supplies.
(This, plus the carbon cost, is why we don't sell distillers).
But distillation certianly does remove dangerous heavy metals like lead, arsenic, and mercury. (As does Reverse Osmosis).
Pro’s and Con’s of Distilling Water
- Distillation is energy intensive ie you have to boil the water. (But large scale / industrial solar desalination plants are quite green)
- It’s quite slow to produce the water
- There’s the issue of the loss of minerals - see below
- The water can taste “flat” - which many people find unappealing (and which some allege can lead to less desire to drink / reduced consumption and subtle dehydration)
- There might be some decrease in the body’s metabolic function
- Drinking distilled water reportedly leads to more urine production which can lead to an electrolytic imbalance
The Issue of the Loss of Minerals
While it’s true that distilled water doesn't have minerals and calcium this is something of a red herring because you should be getting these from a good varied diet.
If you were only going to rely on these from your water you’d already be in serious trouble.
So distilled water is safe to drink in moderation but if it’s the only water you drink it can be problematic.
Health issues might result from the lack of minerals plus disruption to the body’s balance of electrolytes, fluid, minerals and pH.
If you only drink distilled water - and don’t have a good food diet - you might get “acidosis” - when the pH of your blood falls below 7.35. (Your blood pH should be between 7.35 and 7.45).
This is rare but the World Health Organization says it’s related to the lack of electrolytes in distilled water, which can change your body’s delicate balance of sodium, potassium, zinc, phosphorus and other nutrients.
This can lead to fluid retention, nutrient deficiencies, fatigue, muscle cramps, headache, impaired heart rate and even more dire health consequences, including organ failure.
(This is why drinking distilled water isnt recommended for people with cancer, babies and small children and even athletes).
But the WHO stress that we almost always get the vast majority of minerals from food or supplements, not from drinking water. And distilling water is much better than drinking contaminated water.
Plus the WHO note that other demineralizing water filtration methods can also lead to the same negative health consequences as distilled water including Reverse Osmosis (if not remineralized), nanofilteration, and deionizing.
Tip: If you decide to get a domestic distiller, beware of contaminated equipment - especially in domestic settings ie where your purified water is being contaminated with bugs from dirty equipment.
Plus make sure your container isn't made from cheap suspect plastics that might leach chemicals into the “purified” water. Only buy a distiller from a brand you can trust.
Connecticut Department of Public Health. 2009. Publication No. 7: Distillation Treatment Systems for Private Drinking Water System.
World Health Organization. 2009. Calcium and Magnesium in Drinking Water.