Distilled water attracts some strong claims, most of which circulate without much examination. Taking them one at a time is more useful than a general reassurance, because two of them contain a grain of something real and the rest do not, and knowing which is which lets you decide for yourself rather than on the strength of an assertion.
The claim that it leaches minerals from the body
The argument is that water with nothing dissolved in it is a strong solvent and will therefore strip minerals from you. Water is indeed a good solvent, and that property is real in a kettle or a pipe. In the body, what you drink is immediately mixed with saliva, stomach contents and everything else present, and the body's mineral balance is regulated by processes far more powerful than the composition of one glass. The claim takes a true property of the water and applies it somewhere it does not operate.
The claim that it is acidic and harmful
Freshly distilled water is slightly acidic, because it absorbs carbon dioxide from the air as it cools, and that is genuinely measurable. It is also true that the stomach is far more acidic than any drinking water, and that the body regulates blood pH within tight limits regardless of what is drunk. The pH of the water you drink is not a meaningful input to that system. Where the acidity does matter is to plumbing and containers, which is a materials question rather than a health one.
The mineral intake point, which is the real one
The USGS describes hardness as dissolved calcium and magnesium, and distillation removes them along with everything else, so water stops being a source of either. For someone eating normally food supplies the great majority of both, so this is not a route to deficiency. It carries more weight where a diet is already low in those minerals, and it is the reason remineralization stages exist on treatment systems: a similar reduction with a small mineral content restored.
The practical objection nobody argues about
It tastes flat, and that is the reason most households who try drinking it stop. Minerals are much of what gives water its character, particularly in tea and coffee where they affect extraction. If you want thoroughly treated drinking water that still tastes like water, reverse osmosis with a remineralization cartridge is the practical route, and it costs less over a year than buying distilled water. Our softener guide covers the separate question of hardness across a house.
Questions people ask about is it bad to drink distilled water
Does distilled water leach minerals from the body?
No. It is a good solvent in a kettle or a pipe, but what you drink is immediately mixed with everything else in the digestive system.
Is distilled water acidic?
Slightly, from absorbing carbon dioxide as it cools. The stomach is far more acidic, and the body regulates blood pH regardless.
Will it cause a mineral deficiency?
Not for someone eating normally, since food supplies the great majority of calcium and magnesium intake.
So why do most people stop drinking it?
The taste. It is flat, noticeably so in tea and coffee, which is why remineralization stages exist on treatment systems.