Sparkling water has become the default order for people who want something more interesting than still water but are done with sugary drinks. It has also collected a surprising amount of folklore along the way — that it strips calcium from your bones, that it dissolves your teeth, that it does not really hydrate you. Most of that is wrong, and the parts that are not wrong are narrower than people think.
Here is the honest version, with the caveats left in.
What sparkling water actually is
Carbonated water is water with carbon dioxide dissolved into it under pressure. When that gas meets water, a small proportion of it reacts to form carbonic acid — a weak acid that breaks back down into water and gas the moment the pressure drops. That is the fizz escaping when you open the bottle, and it is also the source of the slight bite on your tongue. The tingle is not just bubbles touching you. Your mouth genuinely registers mild acidity, which is why sparkling water tastes sharper than the same water flat.
Beyond that, plain sparkling water is water. No sugar, no calories, no sweeteners, no caffeine. Names differ — seltzer, soda water, club soda — depending on whether salts were added and whether the carbonation was natural or pumped in. They behave much the same.
Does it hydrate you as well as still water?
Yes. This is the one that surprises people most.
Researchers have compared drinks head to head using a measure called the beverage hydration index, which tracks how much of a drink your body holds on to over the following few hours rather than passing straight through. Plain sparkling water came out level with still water. Fluid retention over four hours was no different. Earlier work on rehydration after exercise reached the same conclusion — carbonated drinks replaced fluid just as effectively as flat ones.
So if you drink sparkling water all day instead of still, you are not quietly running a deficit. It counts. The only practical caveat is a behavioural one: some people drink less of it in a sitting because the gas makes them feel full sooner, which brings us to the next point.
Does it fill you up?
Somewhat, and briefly. The gas expands in the stomach, and that stretching is one of the signals your body uses to decide it has had enough. Studies measuring fullness after drinking carbonated water do find higher fullness scores than after still water.
Whether that translates into eating less over a whole day is far less clear, and the research on appetite hormones is genuinely mixed. Treat it as a mild, short-lived effect that some people find useful before a meal, not as a weight-loss tool. Anyone selling it as the latter is overreaching.
The bone myth, and where it came from
The claim that fizzy drinks leach calcium from your bones has been repeated for decades. It has a real study behind it — and that study says something different from what people quote.
Researchers working with data from the Framingham Osteoporosis Study looked at around 2,500 men and women and compared their drinking habits against bone mineral density measured at the hip and spine. Cola drinkers — women in particular — had measurably lower bone density at the hip. Drinkers of other carbonated beverages did not. The association simply was not there for non-cola fizzy drinks at any site measured.
The suspects in cola are its phosphoric acid, its caffeine and, in the sugary versions, the fact that it displaces milk and other calcium sources from the diet. Carbonation itself was never the mechanism. Plain sparkling water contains no phosphoric acid, no caffeine and no sugar, and there is no good evidence that it affects bone density.
The teeth question — the part that is real
This one deserves a more careful answer, because the honest reply is “it depends what is in the can”.
Tooth enamel begins to demineralise when the mouth turns acidic. Plain, unflavoured sparkling water is mildly acidic — enough to measure, not much more. In laboratory comparisons of drinks ranked by how aggressively they erode enamel, plain carbonated water sits at the gentle end, far below cola, energy drinks, diet soft drinks and fruit juice. Orange juice is considerably harder on enamel than soda water is.
The ones worth watching are the flavoured varieties. Citrus flavourings, “with a hint of lime” and similar additions usually mean added citric acid, and citric acid drops the acidity of the drink well below where plain carbonated water sits. Sugar-free does not mean acid-free. Research comparing flavoured sparkling waters against plain versions has found the flavoured ones measurably more erosive, even while still ranking below regular soft drinks.
Practical version: plain sparkling water in a glass you finish is not a dental problem. Sipping flavoured citrus fizz slowly across an afternoon is the habit that does damage, because your teeth never get a break. Keep flavoured versions to mealtimes, use a glass rather than nursing a bottle for hours, and do not brush immediately afterwards — enamel is softest right after acid exposure.
Who should be careful
Some people should simply drink less of it, and they usually already know who they are.
- Reflux and heartburn. Gas raises pressure in the stomach, and that pressure can push the valve at the top of the stomach open. The evidence is mixed on whether fizzy drinks cause reflux, but health bodies commonly advise people who already have it to cut carbonated drinks and see whether symptoms settle. That is a sensible personal experiment.
- IBS and bloating. Carbonation does not cause irritable bowel syndrome, but swallowed gas has to go somewhere. If you are prone to bloating, fizzy drinks are a reliable way to make an uncomfortable day worse.
- Anyone recovering from certain stomach procedures may have been told to avoid carbonation specifically. Follow the medical advice you were given rather than a website.
For everyone else, there is no upper limit worth worrying about.
So what is the actual case for it?
Not that it is healthier than still water. It is not, and nobody should pretend otherwise.
The case is displacement. Plenty of people do not want plain still water with lunch, and if sparkling water is not there, the thing they reach for is a soft drink with nine or ten teaspoons of sugar in it. Swapping that for carbonated water removes the sugar entirely while keeping the thing they actually wanted — something cold with texture and bite that feels like a drink rather than a duty. In a country where sugary drinks are cheap and everywhere, that is a genuinely worthwhile trade.
Add a squeeze of fresh lemon, a few mint leaves or slices of cucumber and it holds its own next to anything on a restaurant menu, at no cost and with nothing added that you would not put in yourself.
Making it at home, honestly
If you buy sparkling water in bottles, you are paying for packaging, transport and storage far more than for water. Carbonating on site removes all three, along with the crates of glass and plastic.
One thing to be clear about, because it is a common misunderstanding: an ordinary under-sink or countertop drinking-water filter does not make sparkling water. Filtration and carbonation are different jobs. A filter improves what comes out of the tap; it has no way to dissolve gas into it. Any system that produces sparkling water has a separate carbonation unit and a CO2 cylinder behind it.
At WaterClub, sparkling water is available on two machines — Fizzy and Aqua Bar — and both are built for volume rather than for a family kitchen. They are the machines we put into offices, restaurants, cafés, gyms, clinics and hotels, where still, chilled and sparkling water are all being poured through the day and the alternative is somebody carrying in cases of bottles every week. If that is your situation, they are worth looking at. If you are filtering water for a household, our other systems will improve the water considerably but will not make it fizz, and we would rather say so up front than let you find out after installation.
You can see the full range, commercial machines included, on the WaterClub shop — and if you are not sure which category you fall into, the filter finder takes a couple of minutes.