These are two entirely different physical processes that happen to arrive at similar-looking water. Distillation changes the water's state, evaporating it and condensing it back, leaving heavier material in the pot. Reverse osmosis never changes state at all: it pushes water through a membrane against its natural direction of flow and sweeps the rejected material away in a separate stream.
Distillation: separation by boiling point
Heat the water and it evaporates. Dissolved minerals, salts, most metals and any solid material cannot follow, because they will not evaporate at that temperature, so they stay in the boiling chamber and eventually build up as scale. The steam travels to a cooler surface, condenses and drips into a collection vessel. The heat also deals with organisms along the way. The blind spot is anything that evaporates at or near water's boiling point, since those compounds ride across with the steam unless a carbon stage traps them.
Reverse osmosis: separation by pressure and pore size
Osmosis naturally moves water toward the more concentrated side of a semipermeable membrane. Apply pressure on the concentrated side, greater than the osmotic pressure, and you reverse that flow: water crosses to the clean side while the dissolved load stays behind. Mains pressure supplies the push in a domestic system. The rejected material has to be flushed continuously off the membrane surface, which is why every reverse osmosis unit produces a drain stream as well as a product stream.
How each one fails
A distiller fails visibly. The chamber scales, output slows, and the appliance looks obviously neglected. A reverse osmosis system fails invisibly: a fouled or torn membrane keeps producing water at what feels like a normal rate while rejecting far less, which is why owners are told to compare feed and product readings periodically. Prefilters exist to prevent that, taking out sediment and chlorine that would otherwise damage the membrane material.
Which suits a whole house
Distillation does not scale to a house. It is a batch process with a heating element, and no practical version supplies showers and laundry. Whole-house reverse osmosis does exist, but it is a substantial installation: a storage tank, a repressurisation pump, prefiltration matched to the incoming water and often remineralisation afterwards, because water that aggressive is unkind to copper pipework. Our whole-house reverse osmosis guide covers when that scale of system is justified.
Questions people ask about distillation vs reverse osmosis
Which process removes more, distillation or reverse osmosis?
They overlap heavily. Distillation handles microbes inherently, while reverse osmosis rejects a broad range of dissolved substances continuously.
Does reverse osmosis use electricity?
A standard under-sink unit runs on mains water pressure alone. Larger or whole-house systems add a pump, which does need power.
Why does distilled water need a carbon stage?
Because compounds that evaporate near water's boiling point can carry over with the steam, and carbon traps them after condensation.