Reverse osmosis vs distilled water

Which is better for your drinking water?

Stasis Home ResearchEvery claim on this page is graded against peer-reviewed health research and linked to its primary source.Updated July 2026

For home drinking water, reverse osmosis is the practical choice over distilled. Both strip water down to very low mineral content and remove the same broad range of contaminants, but RO does it at the tap with no boiling, no waiting, and no electricity, and its carbon stages catch volatile chemicals a still can carry over. Distillation earns its place mainly for specialty non-drinking uses.

How they differ

The two methods reach a similar endpoint by opposite routes. Reverse osmosis pushes water through a semipermeable membrane under household pressure, so dissolved metals, salts, PFAS, and most larger molecules are too big to pass and get flushed to the drain, while a certified system's carbon stages catch chlorine byproducts and solvent-type chemicals. Distillation boils water to steam and condenses it back to liquid, so anything that does not vaporize, minerals, metals, nitrate, PFAS, and microplastic particles, is left behind in the boiling chamber. The real gap is on the volatile end: compounds that boil at or near water's boiling point, some VOCs and disinfection byproducts, can travel with the steam and recondense into the collected water unless the still vents them off first. RO's carbon stages remove those at the tap. Both also strip calcium and magnesium, which is where the minerals question comes up.

Side by side

How Reverse osmosis and Distilled water handle each concern.
Concern	Reverse osmosis	Distilled water
PFAS	YesRemoved more than 94 percent across long- and short-chain PFAS in a 73-home field study (Herkert et al., 2020), the most consistent filter across the full range.	YesThe PFAS acids are not appreciably volatile at water's boiling point, so the bulk of them stay behind in the boiling chamber.
Lead and dissolved metals	YesA system certified to NSF/ANSI 58 for lead reduction removes the large majority of dissolved lead, typically 97 percent or more, and the sediment pre-stage catches particulate lead flakes.	YesMetals do not vaporize, so they remain in the boiling chamber rather than carrying into the condensate.
Nitrate	YesRoughly 75 to 95 percent removal depending on membrane and feed level; carbon filters do not touch nitrate and boiling concentrates it.	YesNitrate salts are nonvolatile, so distillation leaves them behind.
VOCs and volatile organics	YesThe carbon stages before and after the membrane remove solvent-type chemicals; this is exactly what carbon is good at.	PartlyVOCs that boil at or below water's boiling point can co-distill and recondense into the collected water unless the still vents them off.
Microplastics	YesMembrane openings are far smaller than microplastic particles, so RO is expected to remove them; direct point-of-use RO measurement is still limited, so treat this as expected rather than crisply quantified.	YesPlastic particles do not vaporize and stay in the boiling chamber.

Pick Reverse osmosis when

You want clean drinking and cooking water at the tap with no daily effort.
You are treating water for a household, not filling bottles by hand.
Boiling every gallon, and the electricity to do it, is a cost you would rather not carry.
You have under-sink plumbing access for a point-of-use unit.

Pick Distilled water when

You need very low-mineral water for a specific non-drinking use like a CPAP humidifier, a steam iron, or aquarium top-off.
You have no plumbing access and prefer producing water in batches on a countertop.
You want the volatile fraction gone too: pair the still with venting or a carbon post-filter, since a plain still can carry some VOCs across.

What it costs, roughly

Market ranges, not Stasis prices. An under-sink RO unit runs roughly 300 to 1,500 dollars installed, then needs a new membrane every 2 to 3 years and fresh carbon stages every 12 to 24 months. A countertop distiller usually has a lower upfront cost but produces water slowly and draws electricity the entire time it runs, so its ongoing cost lands on the power bill rather than in replacement cartridges. RO also sends some water to the drain as concentrate; newer high-efficiency units cut that waste substantially.

Common questions

Is reverse osmosis or distilled water better for drinking water?

For everyday drinking water at home, reverse osmosis is the more practical choice. Both produce very low-mineral water and remove the same broad set of contaminants, but RO delivers it at the tap without boiling, waiting, or the electricity a still uses, and its carbon stages catch volatile chemicals distillation can carry over. Distillation is better suited to specialty non-drinking uses.

Does reverse osmosis or distillation remove minerals, and is low-mineral water bad for you?

Both remove most of the calcium and magnesium along with the contaminants, so both make low-mineral water. For someone on a normal diet this is not a health problem: the World Health Organization sets no minimum mineral level for drinking water, because food, not water, supplies the large majority of dietary minerals. The one honest nuance is magnesium, where tap water can be a meaningful source, so remineralizing RO water is an option, not a requirement.

How does this compare to alkaline water?

Alkaline water is regular water with a higher pH, from added minerals or an ionizer, which is a different axis entirely from filtration. Raising pH does not remove PFAS, lead, nitrate, or other contaminants. If your goal is cleaner water, RO or distillation is the relevant comparison; alkalinity is a taste and marketing claim, not a contaminant-removal method.

How does this compare to spring water?

Spring water keeps its natural minerals and is not treated to remove contaminants, so what is in it depends on the source. In a study of 101 US bottled waters, spring waters carried more PFAS than purified waters, which the authors attributed to reverse osmosis used in most of the purified products (Chow et al., 2021). Spring water is a mineral and taste preference, not a purification step.

How does this compare to deionized water?

Deionized water has its dissolved ions stripped out by ion-exchange resin, so like RO and distillation it is very low in minerals. It is common in labs and industry but is not aimed at the health contaminants a home cares about: ion exchange does not reliably remove uncharged organic molecules or microbes, so it is not a substitute for RO or distillation for drinking water.