Distillation and reverse osmosis arrive at a similar destination by completely different routes, and for household drinking water the output is largely interchangeable. The decision is about energy, production rate, plumbing and what each process fails to catch, rather than about which one is purer.
Two different mechanisms
Distillation boils water to steam and condenses it back, leaving behind anything that does not evaporate. Reverse osmosis pushes water through a semipermeable membrane using line pressure, leaving dissolved solids on the feed side to be flushed away in a reject stream. One is a phase change driven by heat, the other a separation driven by pressure, and that difference decides every practical consequence that follows.
What each one misses
Distillation carries over anything that boils at or below the temperature of water, so volatile organic compounds can appear in the condensate unless the still has a vent or a carbon stage. Reverse osmosis passes some dissolved gases and certain low molecular weight volatiles, which is why carbon stages sit before and after the membrane. Distillation guarantees removal of bacteria and viruses through the phase change; a membrane in good condition rejects them well but its condition has to be verified rather than assumed.
Running cost and daily practicality
Distillation spends electricity boiling every liter, works in batches and is slow, so it means planning ahead and it sits on a worktop taking space. Reverse osmosis in a conventional tank system uses no power at all, produces continuously into storage, and gives a tapful on demand, at the cost of cartridges and a membrane periodically plus the water sent to drain. For everyday household volume, reverse osmosis wins clearly on both cost and convenience.
Where each is the correct choice
Choose distillation where there is no pressurized supply to drive a membrane, where the source is genuinely unknown and the certainty of a phase change is worth the slowness, or for equipment such as steam irons and CPAP machines. Choose reverse osmosis for a household drinking and cooking supply. Both outputs taste flat, since taste in water is largely dissolved minerals, so both benefit from a remineralizing stage. Our reverse osmosis guide covers system sizing.
Questions people ask about distilled water vs reverse osmosis
Which is purer, distillation or reverse osmosis?
Close to equivalent for dissolved solids. Distillation guarantees organism removal by phase change; reverse osmosis may pass some dissolved gases.
Which costs less to run?
Reverse osmosis, by a wide margin. It uses line pressure rather than electricity, though it does send a reject stream to drain.
Can distilled water still taste odd?
Yes. Volatile organics boiling near water can carry over into the condensate unless the still has a vent or a carbon stage.
Do both need remineralizing?
For taste, generally yes. Both remove the dissolved minerals that give water its character, so the output tastes flat.