Is Sparkling Water as Hydrating as Still Water?

If plain water bores you and sparkling water doesn't, you've probably wondered whether the bubbles cost you anything. Does carbonated water “count”? Is it worse for your teeth? Does it bloat you? The short version: sparkling water hydrates you just as well as still water, and most of the worries about it are either overblown or easy to manage. The longer version is below.

What sparkling water actually is

Sparkling water is water with carbon dioxide dissolved into it under pressure. That's it. When the pressure is released, the gas comes out of solution as bubbles, and a small amount of it reacts with the water to form carbonic acid — which is what gives sparkling water its faint sharpness. Seltzer, club soda, and naturally sparkling mineral water are all variations on this theme; they differ mainly in whether any minerals or salts have been added or were present in the source.

Does it hydrate as well as still water?

Yes. Your gut absorbs water from a carbonated drink the same way it absorbs it from a flat one; the carbon dioxide mostly leaves as a burp and plays no role in how much fluid ends up in your bloodstream. The best-known study on this question, a 2016 trial published in the American Journal of Clinical Nutrition that produced a “beverage hydration index,” compared how long various drinks kept fluid in the body relative to still water. Sparkling water performed indistinguishably from still water. Milk and oral rehydration solutions scored higher because of their electrolytes and energy content, but bubbles alone made no difference either way.

So if your daily fluid target is around two liters — see how that number is derived — a liter of sparkling water gets you exactly as far as a liter of tap water. The one caveat, which we'll get to, is that some people find it harder to drink as much of it.

Is it bad for your teeth?

This is the most common concern, and it deserves a nuanced answer. Carbonic acid does make sparkling water mildly acidic — typically a pH around 5 to 6, compared with roughly 7 for still water. Tooth enamel begins to soften below about pH 5.5, so in theory plain sparkling water sits right at the edge. In practice, studies that have exposed extracted teeth to plain carbonated water found minimal erosion, because the acidity is weak and saliva neutralizes it quickly.

The contrast with soda is enormous. Colas and many fruit-flavored fizzy drinks sit around pH 2.5 to 3.5, and they combine that acidity with sugar that feeds acid-producing bacteria. Diet sodas skip the sugar but keep the phosphoric or citric acid. Plain sparkling water is on a completely different scale, and swapping soda for it is one of the better things you can do for your teeth. If you drink a lot of it, sensible habits help: don't swish it around, rinse with still water afterward if you like, and avoid brushing immediately after any acidic drink.

Flavored versus plain

This is where the teeth question gets more real. “Natural flavors” are usually harmless, but many flavored sparkling waters add citric acid for brightness, and citric acid is a meaningful step up in erosiveness. Lemon and lime varieties tend to be the most acidic — some measure as acidic as diet soda. If you're drinking several cans a day, plain is the safer default and flavored is best treated as an occasional variation. Check the ingredients: if citric acid appears near the top, that's the one to go easy on. And if a “sparkling water” lists sugar or sweeteners, it's a soft drink wearing a healthier label.

Bloating and fullness

The gas has to go somewhere. For most people, that means a burp and a brief feeling of fullness; for some — especially those with reflux, irritable bowel syndrome, or a sensitive stomach — it can mean genuine discomfort. There's no evidence that sparkling water is harmful here, but if it makes you uncomfortable, that's reason enough to stick with still.

The fullness effect cuts both ways. Some people find a glass of sparkling water before a meal helps them eat a little less, which is occasionally cited as a small benefit. But it also means you may naturally drink less of it than you would of still water, which matters if you rely on sparkling water for most of your daily intake. If you notice you're consistently short on days you drink only fizzy water, that's the fullness talking, not a hydration problem with the water itself.

A note on sodium in mineral waters

Club soda and many naturally sparkling mineral waters contain added or native sodium bicarbonate and other minerals. The amounts vary enormously by brand — from essentially nothing to over 1,000 milligrams per liter. For most healthy people a glass now and then is irrelevant, but a liter of a high-sodium mineral water can supply close to half a day's recommended sodium. But if you've been told to limit sodium, it's worth reading the label rather than assuming “water” means “salt-free.” Plain seltzer, which is just water and carbon dioxide, has none.

How to count it in a tracker

Simply: one to one. A 330 ml can of plain sparkling water is 330 ml of hydration, no discount required, no bonus either. That's true for seltzer, club soda, and mineral water alike; it's also true for flavored sparkling water as long as it contains no sugar or caffeine. In Realwater, log it as a regular drink of whatever size you had — the app doesn't need to know it was fizzy, because your body doesn't either. The only drinks that deserve different treatment are ones with meaningful caffeine, alcohol, or sugar, and we cover those separately in our piece on coffee and tea.

Which leaves the practical takeaway: if bubbles get you to drink more water than you otherwise would, that's a win worth taking. Prefer plain over flavored when you can, listen to your stomach, keep an eye on sodium if it matters for you, and count every glass at full value. The fizz is free.

This article is for general information and isn't medical advice. If you have reflux, a sodium-restricted diet, or dental concerns, your doctor or dentist can give guidance specific to you.