Distilled water is made one way: the water is boiled, the vapor is captured, and it condenses back into a clean container leaving dissolved solids behind in the boiler. Purified is a broader description covering any process that strips most dissolved matter, distillation included. So all distilled water is purified, but plenty of purified water was never boiled at all.
How distillation works and what it leaves behind
A home distiller heats water until it turns to steam, which rises away from anything that cannot evaporate with it. Dissolved calcium and magnesium, sodium, metals, nitrate and most other dissolved solids stay in the boiling chamber and build up as a hard deposit you scrape or descale out. The condensed product is close to free of minerals. The process is slow, it uses a meaningful amount of electricity for each batch, and it produces water by the gallon rather than on demand, which is what usually decides against it for whole household drinking.
What purified normally means in practice
In everyday use, purified water is water whose dissolved solids have been reduced to a very low level, whichever route got it there. In houses that is nearly always reverse osmosis, sometimes followed by a deionizing resin. Both distillation and reverse osmosis remove the same broad class of dissolved constituents, and they differ in throughput, in energy source and in what they miss. Distillation can carry over volatile organic compounds that boil alongside the water unless the unit has a carbon post filter, while membranes reject those poorly too and rely on carbon for the same reason.
Neither one is a softener
Both processes take out the hardness minerals, because the USGS defines hardness as dissolved calcium and magnesium and both methods strip dissolved matter broadly. But neither is a practical answer to a hard water household, because you cannot shower, run a dishwasher or fill a water heater from a countertop distiller or a small membrane. Scale is a whole house problem and needs a whole house solution. If that is what you are actually solving, our water softener installation guide is the page you want, not this one.
Choosing between them at home
Buy a distiller if you want a batch of mineral free water for a steam iron, a humidifier, a CPAP machine, an aquarium top up or a lab style use where consistency matters more than convenience. Choose reverse osmosis if you want treated drinking water on demand at the kitchen sink with no batch to run and no chamber to descale. If flat taste is the objection, both can be followed by a remineralizing cartridge that puts a small amount of mineral content back for palatability.
Questions people ask about distilled vs purified water
Is distilled water safer than purified water?
Neither is inherently safer. They remove a similar range of dissolved matter, and both depend on a carbon stage to deal with volatile organic compounds.
Can I use reverse osmosis water where distilled is specified?
Usually yes for appliances such as steam irons and humidifiers, though equipment makers sometimes specify distilled because it is the more predictable product.
Why does distilled water taste flat?
The dissolved minerals that give water its flavor stay behind in the boiler. A remineralizing cartridge or a pinch of mineral blend restores the taste if you want it.
Does a distiller need maintenance?
Yes. Everything the water leaves behind builds up as scale in the boiling chamber, so it needs regular descaling and periodic carbon post filter changes.