Both distillation and reverse osmosis leave you with water carrying very little dissolved content, so the everyday difference is not purity, it is what you can do with the result. Reverse osmosis water can be adjusted before it reaches your glass, distilled water arrives as it is, and both behave differently from ordinary tap water once you store them.
Why both taste flat, and what causes it
Flavor in water comes largely from its dissolved mineral content: calcium, magnesium, bicarbonate and trace salts. Take those out and the water tastes thin, soft and slightly empty, which is a common first reaction to both distilled and reverse osmosis water. The sensation is identical between the two because the cause is identical. People who dislike it are not detecting a difference between the technologies, they are detecting the absence of minerals that both technologies remove.
Only one of them can be adjusted
This is the real practical distinction. Reverse osmosis systems are commonly fitted with a remineralization stage after the membrane, a small cartridge of calcite or mineral media that returns a controlled amount of calcium and magnesium to the water and lifts the pH slightly. The result tastes fuller and suits coffee brewing better. A distiller has no equivalent, because there is nowhere in the process to add anything back. If taste matters to you, that option only exists on the reverse osmosis side.
How each one is produced and where the differences hide
The mechanisms diverge in what escapes them. Distillation separates water by boiling point, so compounds that boil at or below water can carry over into the condensate unless a carbon stage catches them, which is why quality distillers include one. Reverse osmosis separates by membrane rejection, which handles dissolved salts extremely well while relying on carbon prefilters to keep chlorine away from the membrane. Neither weakness matters much in a well maintained unit, and both matter in a neglected one.
Storage and what the water touches
Water with very little dissolved content is more inclined to pick things up from what it touches, so both are stored in glass or food grade plastic rather than in metal containers. Neither carries a disinfectant residual, so a container that is not clean will grow something eventually. Reverse osmosis water sits in a pressurized tank inside your cabinet and is used continuously, which keeps it turning over. Distilled water in an opened jug on a shelf is the one more likely to sit for weeks.
Which to have in the house
For daily drinking and cooking, a reverse osmosis system with a remineralization stage gives you water that tastes like water and costs nothing per glass once installed. For occasional appliance use where a manual names distilled, buy the jug. The two are not competitors so much as different answers to different frequencies of need. Our reverse osmosis water filter cost page covers what the plumbed option runs to buy and to keep fed.
Questions people ask about difference between distilled water and reverse osmosis water
Can reverse osmosis water be remineralized?
Yes, with a post membrane cartridge of mineral media that adds back a controlled amount of calcium and magnesium. It improves taste and raises the pH slightly, and distillation offers no equivalent step.
Is one more acidic than the other?
Both tend to sit slightly on the acidic side once they absorb carbon dioxide from the air, which is normal for water with little mineral buffering. A remineralization stage on a reverse osmosis system offsets it.
Should I store either one in metal bottles?
Use glass or food grade plastic. Water with very little dissolved content is more inclined to take up material from its container, and metal is the container type most worth avoiding.
Do both remove hardness?
Yes, entirely, since calcium and magnesium are exactly what both processes leave behind. Neither is a whole house answer though, because both treat only the water at one point of use.