Distilled water is water that has been boiled and its vapor condensed, leaving almost everything else behind. It is safe to drink, which is the short answer, and the longer answer is about taste, about where your minerals actually come from, and about a few specific situations where the absence of dissolved material has practical consequences.
Why it tastes flat
Most of what people recognise as the taste of water is dissolved mineral content. The USGS describes hardness as dissolved calcium and magnesium, and those two, along with bicarbonates and a little sodium, give ordinary tap water its character. Distillation removes essentially all of it, so what is left tastes of nothing, which many people find unpleasant rather than pure. The same effect appears with reverse osmosis water, which is why remineralization cartridges exist. It is a taste question, not a safety one, and it is the reason most households do not drink distilled water by choice.
The minerals argument, in proportion
The concern raised about distilled water is that drinking demineralized water deprives you of calcium and magnesium. It is worth keeping in proportion: for most diets, food provides the great majority of mineral intake and water a small fraction of it. Someone eating normally is not going to develop a deficiency by drinking distilled water. The argument carries more weight where water is a person's main mineral source, which is unusual in practice, and it is not a reason to avoid distilled water occasionally or during a supply problem.
Where distilled water is the right choice
There are jobs where the absence of dissolved solids is exactly the point. Steam irons, humidifiers and CPAP machines all benefit, because ordinary water leaves scale and mineral dust behind as it evaporates. Car batteries and cooling systems specify it. Some laboratory and medical uses require it. And it is the reference water for anything where minerals would interfere. Households that buy distilled water usually do so for one of these reasons rather than for drinking, which is a sensible way round.
If you are drinking it because of your tap water
People often switch to distilled or bottled water because of a taste, a smell or a worry about the supply. That is treating the symptom expensively. Establish what is actually in the water first, then treat it: a carbon filter for chlorine taste, a softener for scale, reverse osmosis with a remineralization stage for a broad reduction that still tastes like water. All of those cost less over a year than carrying bottles. Our water testing guide covers finding out what you are dealing with before spending on equipment.
Questions people ask about is it okay to drink distilled water
Is distilled water safe to drink?
Yes. It is simply water with the dissolved material removed. The common objections are about taste and about mineral intake, not about safety.
Why does distilled water taste flat?
Because the dissolved minerals that give water its taste have been removed. Reverse osmosis water tastes similar, which is why remineralization cartridges are sold.
Will drinking it cause a mineral deficiency?
Not for someone eating a normal diet, where food supplies the great majority of calcium and magnesium intake and water contributes a small share.
What is distilled water normally used for?
Appliances where scale matters: steam irons, humidifiers, CPAP machines, car batteries and cooling systems, along with laboratory and medical uses.