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Reverse Osmosis vs Spring vs Distilled Water: What's the Difference (and What's Best)?

Updated September 2026·9 min read

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Reverse osmosis, spring, and distilled are the three “premium” waters people compare when they want something better than straight tap, and they really are different. One is purified by a membrane, one comes from the ground with its minerals intact, and one is boiled and recondensed, leaving most impurities behind. They differ in how clean they are, whether they keep minerals, how they taste, and what they cost. This guide lays out the differences and tells you which makes sense for daily drinking and for specific uses.

Quick Comparison

Reverse Osmosis Spring Water Distilled Water
How it’s made Forced through a fine membrane Collected from a natural spring Boiled, then steam recondensed
Purity Very high (membrane removes most dissolved solids) Variable; not purified Very high
Keeps minerals? No (unless remineralized) Yes (natural minerals) No
Taste Clean, “flat” unless remineralized Natural; many people prefer it Flat / bland
Cost System up front, then filter changes Ongoing bottle purchases Distiller up front, then electricity
Convenience On tap Buying/storing bottles Slow batches
Best for Everyday drinking & cooking Those who want natural minerals Appliances, CPAP (per device maker), specific uses

Reverse Osmosis Water

Reverse osmosis water is tap water forced under pressure through a membrane so fine it removes most dissolved solids, including many heavy metals, fluoride, nitrates and PFAS (check a system’s NSF/ANSI 58 certification for the specific reductions it claims). (See What Is Reverse Osmosis Water? for the full mechanism.)

  • Purity: Very high for a home system.
  • Minerals: Removed along with contaminants, so RO water is “demineralized” and can taste flat, though many systems add a remineralization stage to restore taste and minerals.
  • Cost & convenience: This is RO’s big advantage. Once installed, you get purified water on tap; the ongoing cost is replacement filters, with nothing to buy or carry.
  • Best for: Everyday drinking and cooking. RO balances purity, running cost, and convenience well for many households. Choose a remineralizing model if you want the minerals and taste back.

See our best reverse osmosis systems guide for under-sink picks, or the countertop guide for renters.

Spring Water

Spring water comes from an underground source and is bottled (or sometimes collected) with its natural minerals intact.

  • Purity: Variable. Spring water is not purified the way RO or distilled water is. Bottled spring water must meet bottled-water standards, but it can still contain whatever minerals and trace contaminants the source carries. “Natural” doesn’t mean contaminant-free.
  • Minerals: Its main selling point. Natural calcium, magnesium, and other minerals give it taste and a small nutritional contribution.
  • Cost & convenience: An ongoing purchase, and the least convenient of the three for regular use. You’re buying, carrying, and storing bottles, often in plastic. And bottled water (spring included) has been found to contain microplastics.
  • Best for: People who specifically want naturally mineralized water and don’t mind the ongoing cost.

Distilled Water

Distilled water is made by boiling water into steam and condensing it back to liquid, leaving most impurities (and minerals) behind.

  • Purity: Very high, comparable to RO. (Some volatile compounds can carry over with the steam, which is why some distillers add a carbon filter.)
  • Minerals: Removed, so distilled water is demineralized and tastes flat/bland, for the same reason pure RO water does.
  • Cost & convenience: You can make it at home with a countertop distiller, but it’s slow (the CO-Z below is listed at 0.25 gallons per hour) and uses electricity to boil the water. Less convenient than RO on tap.
  • Best for: Specific uses where mineral-free water matters: CPAP machines and humidifiers (follow the device maker’s instructions), steam irons, car batteries, some appliances, and lab needs. Many people use distilled for those and RO for drinking.

If you want to make distilled water at home:

CO-Z 4L Stainless Steel Countertop Water Distiller

CO-Z 4L Countertop Water Distiller

A 4L countertop distiller with a 304 stainless steel interior, about 0.25 gallons per hour of output, and automatic shut-off at 302°F, according to the listing. It’s an option if you want distilled water for appliances without buying it by the jug. (We swapped in this CO-Z listing in Oct 2026 when the one we linked before went dead.)

Check Price on Amazon →

Head-to-Head: Which Wins?

  • Purity: Distilled ≈ Reverse osmosis > Spring. Distilled and RO are both highly purified; spring isn’t purified.
  • Minerals & taste: Spring > RO/Distilled. Spring keeps natural minerals and taste; RO and distilled are flat unless RO is remineralized.
  • Cost structure: RO (system plus filter changes), Distilled (distiller plus electricity), Spring (ongoing bottle purchases). Which is cheaper for you depends on how much you drink and current prices.
  • Convenience: RO (on tap) > Distilled (slow batches) > Spring (buying/storing bottles).
  • Environmental impact: RO (no bottles) and home distilling beat bottled spring water, which generates plastic waste and food miles.

So Which Should You Drink?

  • For everyday drinking and cooking: Reverse osmosis is a strong all-around choice: very pure, on tap, with filter changes as the running cost. If you miss minerals or taste, pick a remineralizing RO system and you get purity and minerals.
  • For appliances, CPAP, humidifiers, or specific mineral-free needs: Distilled is the usual choice (check your device’s manual). Some homes run RO for drinking and keep a distiller (or buy distilled) for these uses.
  • If you specifically want naturally mineralized water and don’t mind the cost: Spring. Just know it isn’t purified, and bottled water carries plastic and microplastic concerns.

For the deeper health angle on demineralized water (RO and distilled), see Is Reverse Osmosis Water Good for You?.

Cost Over Time

We don’t quote per-gallon figures because prices, usage and local electricity rates vary too much. Here’s what drives each cost:

Water What you pay for Notes
Reverse osmosis (home) System, then filters One-time system cost; replacement filters on the maker’s schedule; some water goes to drain
Distilled (home distiller) Distiller, then electricity Electricity to boil + occasional cleaning
Distilled (store-bought) Every jug Plus carrying jugs
Spring water (bottled) Every bottle Ongoing; plus plastic waste

With bottled water you pay for every gallon; with home RO most of the cost is up front, then filters. The more water your household drinks, the more that structure favors RO. To compare for your home, price the system and its replacement filters against what you currently spend on bottled water. RO also cuts the plastic waste and transport footprint that come with bottles.

FAQ

Is reverse osmosis water the same as distilled water?

They’re similar in purity but made differently. Distilled water is boiled and recondensed; RO water is filtered through a membrane. Both are highly purified and demineralized. For drinking, they’re comparable. RO is more convenient at home (on tap vs slow batches).

Which is healthiest: reverse osmosis, spring, or distilled?

We don’t give medical advice; the trade-off is contaminant removal versus mineral content. RO and distilled are the purest (fewest contaminants) but demineralized; spring keeps minerals but isn’t purified. For most people food is the larger mineral source, and remineralized RO is a middle ground. If you have a specific health concern, ask your doctor. See our full health breakdown.

Can I drink distilled water every day?

Some people drink it routinely. It’s very pure and mineral-free, so it tastes flat and contributes no minerals; the WHO has raised questions about relying on demineralized water mainly for people whose diets are low in minerals. If you plan to drink it as your only water, it’s worth asking your doctor. See our health breakdown.

Is spring water purified or filtered?

Bottled spring water has to meet bottled-water standards, but it is not purified the way RO or distillation purifies. It retains its natural minerals and can carry trace contaminants from the source. “Natural spring water” is a source description, not a purity guarantee.

Is reverse osmosis or distilled better for a CPAP machine?

CPAP and humidifier makers commonly specify distilled water, because it’s mineral-free and won’t leave scale. Follow your device’s manual; if it calls for distilled, make it with a countertop distiller or buy it.

Why does reverse osmosis and distilled water taste flat?

Because both remove the dissolved minerals (calcium, magnesium, bicarbonates) that give water its familiar taste. For most people it’s a taste issue. A remineralizing RO system adds those minerals back if you find pure water too flat.

Is reverse osmosis cheaper than buying bottled water?

Usually, over time, if you drink a lot of bottled water. After the upfront system cost, you pay for replacement filters rather than every gallon. How fast it pays back depends on the system, the filter schedule, and how much bottled water you currently buy, so price those for your household. It also cuts plastic waste.

Which water is best for making coffee or tea?

Many coffee and tea enthusiasts prefer slightly remineralized RO water. It’s clean enough to let the coffee or tea flavor come through, with just enough minerals for good extraction and taste. Pure distilled or fully demineralized RO can taste flat in a brew; spring water works but varies by source. It comes down to taste.

Bottom Line

For everyday drinking, reverse osmosis is a strong choice of the three: very pure and on tap, with filter changes as the running cost and the option to remineralize for taste. Distilled water is the usual pick for appliances, CPAP, and mineral-free needs, but slow to make and flat to drink. Spring water keeps natural minerals and taste, but it isn’t purified, it’s an ongoing purchase, and bottled water carries plastic concerns. A practical setup for many homes is RO for drinking and distilled for specific uses.

To set up RO at home, see our best reverse osmosis systems guide.

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