Reverse Osmosis
Reverse osmosis or distillation: two paths to the same flat taste
Quick answer
Reverse osmosis and distillation both remove dissolved minerals almost completely, and neither one is meaningfully healthier than the other. Distillation boils and condenses water in a slow, energy hungry countertop appliance certified under NSF/ANSI 62. Reverse osmosis is plumbed under a sink and produces continuously, certified under NSF/ANSI 58.
Reverse osmosis and distillation arrive at a very similar result through two completely different processes, and picking between them comes down to how the water is produced rather than which one is somehow purer. Distillation boils water and condenses the steam, leaving dissolved minerals behind in the boiling chamber, and is certified under NSF/ANSI 62. Reverse osmosis forces water through a membrane fine enough to reject most dissolved solids, certified under NSF/ANSI 58. Both remove dissolved minerals almost completely, and neither process makes the resulting water healthier than the other, since the health question in either case is about what was removed and what was not, not about the mechanism.
The real differences are practical. Distillation is slow, uses a meaningful amount of electricity to boil water one batch at a time, and is almost always a countertop appliance producing a gallon or two over several hours. Reverse osmosis is plumbed into the cold water line, runs continuously without supervision, and refills a storage tank in the background. Both leave water with a notably flat taste, which is exactly why remineralization cartridges exist for reverse osmosis systems and are sometimes added after a distiller as well.
How each process actually removes minerals
A distiller heats water to a boil, and the steam that rises leaves behind essentially everything that does not evaporate with it, including calcium, magnesium, sodium and most other dissolved solids. The steam is then condensed back into liquid water in a separate chamber, and what collects there has been through a genuine phase change rather than a mechanical filtration step. NSF/ANSI 62 is the standard that governs residential distillation units. Reverse osmosis takes the opposite approach: it never boils anything, instead forcing pressurized water through a membrane whose pore structure is small enough to reject the great majority of dissolved solids while letting water molecules through, certified under NSF/ANSI 58. Both approaches reach a similarly low total dissolved solids figure at the outlet, even though nothing about how they get there resembles the other.
Speed, footprint and electricity
Distillation is a slow, energy intensive countertop batch process, while reverse osmosis is a continuous, plumbed system that produces in the background.
Published figure A published standard, regulatory limit, unit conversion or manufacturer specification. It does not change because somebody disagrees with it.
| Question | Distillation | Reverse osmosis |
|---|---|---|
| Governing standard | NSF/ANSI 62 | NSF/ANSI 58 |
| Installation | Countertop appliance, no plumbing | Plumbed under the sink, needs a drain |
| Production speed | Roughly a gallon over several hours | Continuous, refills a storage tank |
| Electricity use | Meaningful, water is boiled to steam | Minimal, most conventional systems use none |
| Produces wastewater | No | Yes, at a fixed drain ratio |
| Resulting taste | Flat, minerals removed | Flat, minerals removed |
Neither process is certified as making water safe to drink. Both are dissolved solids reduction methods, and a well supply with a biological result needs that addressed separately from either one.
Why both taste flat, and what people do about it
Calcium and magnesium contribute a noticeable roundness to the taste of water, and stripping them out through either boiling or membrane rejection removes that along with everything else. This is not a defect specific to one technology, it is the direct consequence of removing dissolved minerals by any method, and it is the entire reason remineralization stages exist. A reverse osmosis system such as the APEC Water ROES-PH75 6 Stage Under Sink RO System with Alkaline Stage, 75 GPD adds a stage specifically to put a measured amount of calcium back in after the membrane, restoring some of that taste without meaningfully raising the total dissolved solids figure back toward the original. Distilled water can be remineralized the same way, though it is less commonly sold as a bundled feature the way it is on reverse osmosis systems.
Which one fits a household better
Distillation suits a low volume need, such as topping off a humidifier, a CPAP machine or an iron, where a gallon or two produced overnight is plenty and a plumbing connection is unwanted or impossible, for example in a rental. Reverse osmosis suits ongoing household drinking and cooking water, where continuous, unattended production without babysitting a countertop unit matters more than the appliance being portable. Neither is the right answer for a household whose actual complaint is chlorine taste rather than dissolved solids, since both are considerably more effort and expense than a carbon filter for that specific problem.
Frequently asked questions
Is distilled water healthier than reverse osmosis water?
No. Both remove dissolved minerals almost completely through different mechanisms, boiling and condensing versus membrane rejection, and neither process adds a health benefit the other lacks. The minerals removed by either method are a small part of typical dietary mineral intake for most people. The practical differences that actually matter are production speed, electricity use and whether a plumbing connection is available, not which one is somehow purer.
Why does distilled water taste flat?
Calcium and magnesium contribute a noticeable roundness to the taste of water, and distillation removes them almost completely along with everything else that does not evaporate during boiling. The resulting water is very low in total dissolved solids, and a flat or empty taste is the direct, expected result of that mineral removal rather than a sign anything went wrong with the process.
Can a distiller replace a reverse osmosis system for a whole household?
Technically it can reach a similar total dissolved solids result, but the production rate makes it impractical for most households, since a countertop distiller typically produces only a gallon or two over several hours and uses meaningful electricity doing it. Reverse osmosis is plumbed and produces continuously in the background, which is why it is the more common choice for ongoing household drinking and cooking water rather than occasional use.
Does distillation remove nitrate, arsenic or lead?
Distillation removes the great majority of dissolved solids, which includes these contaminants in most cases, but confirming any of them requires a certified laboratory test rather than an assumption based on the appliance type. Nitrate, arsenic and lead are invisible and tasteless, so a household relying on distillation for any of them should confirm the result with testing rather than trusting the mechanism alone.
Is reverse osmosis wastewater a bigger downside than the electricity a distiller uses?
It depends what the household weighs more heavily. Reverse osmosis sends a portion of incoming water to the drain at a fixed ratio per membrane, while distillation uses electricity to boil water for every batch produced. Neither cost is trivial at scale, and a household deciding between them should compare their own water and power costs rather than assuming one is universally cheaper to run.
Do I need to remineralize distilled water the same way as reverse osmosis water?
The flat taste is caused by the same mineral removal in both cases, so remineralizing helps either one the same way. Reverse osmosis systems more commonly bundle a remineralization stage as a built in cartridge option, while distilled water is remineralized less often in practice, usually by adding a small measured mineral supplement rather than through a built in stage on the appliance itself.
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Researched, not professional advice. This page is compiled from published standards, regulatory limits, manufacturer specifications and owner-review consensus, not hands-on testing. Nothing here diagnoses a water problem or says any product makes water safe to drink. Figures described as a rule of thumb are water treatment trade convention rather than published standards, and they are labeled that way wherever they appear. Test your water before you buy equipment: on city water start with the Consumer Confidence Report your utility publishes each year, and on a private well only a certified laboratory test tells you what you have. Bacteria, nitrate, lead, arsenic and PFAS are not do it yourself topics, they are invisible and tasteless, and they need a laboratory and usually a licensed professional rather than a product. Remember that a certification covers a specific claim under a specific standard, so "NSF certified" with no number attached tells you very little.