Does Sparkling Water Hydrate You as Well as Still?

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Some hydration trackers score sparkling water as a lesser drink, as if the bubbles cancel out the water. They don’t. In the trial that built the Beverage Hydration Index, plain carbonated water hydrated people exactly as well as still water, and it counts toward your daily fluid the same way.

Where the fizz-dehydrates myth comes from

Unlike coffee’s myth, this one doesn’t trace to a single old study. Two separate worries get tangled together here: that the bubbles themselves pull water out of you, and that carbonation strips calcium from your bones. Both probably grew out of confusing sparkling water with cola, a genuinely different drink whose sugar and acidity raise their own separate questions. Carbonation is the one ingredient the two share, so it took the blame for problems that belong to the sugar instead.

What carbonation actually does

Carbonating water just dissolves carbon dioxide gas into it under pressure. Once you swallow it, that gas behaves like any other dissolved gas: some gets released as a burp, the rest passes on through digestion. It forms a small amount of carbonic acid in the process, but your body buffers that easily, and it has no diuretic mechanism, nothing like the pathway caffeine or alcohol use to raise urine output.

Sparkling water scored no differently from still water in the trial that built the Beverage Hydration Index (Maughan et al., 2016).

The bubbles can make a glass feel more filling, which is real, just not a hydration effect. It might slow down how fast you drink it. It doesn’t change how much of it your body keeps.

Sparkling water versus still water

The cleanest test comes from the trial that created the Beverage Hydration Index. Maughan and colleagues (2016) had 72 healthy men drink a liter of water on one occasion and a liter of one of thirteen other drinks on another, then tracked urine output for the four hours after. Sparkling water was one of those thirteen, right alongside coffee, tea, cola and lager, and it landed statistically even with plain water on every measure. Only milk and an oral rehydration solution modestly outlast water, thanks to protein and sodium that help hold fluid in the body longer. Sparkling water carries neither, so it sits right on the water line instead of above it, exactly where you’d expect carbonated water to land.

How to count sparkling water toward hydration

So should a tracker discount sparkling water the way it discounts coffee or tea? Our honest answer: no, there’s nothing here to discount. Coffee and tea carry caffeine, a genuine if mild diuretic, so we shade their credit down a notch on purpose, a nudge toward plain water. Carbonation doesn’t raise that question at all, so Brim doesn’t carry a separate sparkling water entry in its drink list. Log it under Water and it counts at the full 100%, free tier included, no Premium unlock required.

You can see exactly how every other drink in the catalog is credited, coffee and tea included, in the BHI Hydration Index Lookup.

Do the calcium and bloating myths hold up?

Not well. The calcium-leaching claim is a separate, long-running bone-health question, and it isn’t something the hydration trial above measured at all; it shouldn’t factor into whether a glass counts toward your daily fluid. Bloating is real, carbonation does create gas in your stomach, but that’s a comfort issue, not a hydration one. It might make you sip slower. It won’t make the water you drink count for less.

Club soda, seltzer, tonic: same thing?

Plain fizz is plain fizz, whatever the label calls it. Club soda, seltzer and unsweetened sparkling or mineral water are all just carbonated water, sometimes with trace minerals, and all hydrate like still water. Tonic water is the exception: it’s carbonated water built around added sugar and quinine, closer to a soda than to plain water. Flavored sparkling waters split down the middle, some are just water plus natural flavor, others add sugar, so the label decides, not the fizz.

Key takeaways