Plain carbonated water is not bad for you in any meaningful way. It hydrates just as well as still water, doesn’t weaken your bones, and causes roughly the same amount of enamel wear as flat water. The main downside is that the dissolved carbon dioxide can cause gas, bloating, and discomfort, especially if you drink a lot of it or already deal with acid reflux. Flavored varieties with citrus additives deserve a bit more caution.
It Hydrates the Same as Still Water
One of the most common concerns is that carbonated water somehow doesn’t “count” as real hydration. It does. In a study where participants drank either a liter of still water or sparkling water, researchers measured urine output after four hours and found no difference in hydration status between the two groups. If you prefer the fizz and it helps you drink more water throughout the day, that’s a net positive.
Tooth Enamel: Plain vs. Flavored
Carbonation does make water slightly more acidic, which raised early concerns about enamel erosion. But when researchers tested extracted human teeth in sparkling water versus regular lab water, the two were about the same in their effects on enamel. The American Dental Association considers sparkling water far better for your teeth than sugary drinks like soda or juice.
The exception is citrus-flavored sparkling water. Lemon, lime, and grapefruit varieties often contain citric acid, which raises acidity levels enough to increase your risk of enamel damage over time. If you regularly drink flavored sparkling water, rinsing with plain water afterward or not sipping it slowly over hours can reduce your exposure.
Bone Density Is Not Affected
The idea that carbonated drinks weaken bones comes from research on cola, not sparkling water. Cola contains phosphoric acid, and there was a theory that it could interfere with calcium absorption. Even that theory hasn’t held up well. In the Framingham Osteoporosis Study, researchers examined bone mineral density data from about 2,500 men and women between ages 49 and 69. Non-cola carbonated drinks showed no association with low bone density at all. Cola was linked to slightly lower hip bone density in women only, likely due to other dietary factors (like replacing milk with soda) rather than the carbonation itself.
A clinical trial published in the British Journal of Nutrition confirmed this more directly. Healthy postmenopausal women, a group particularly vulnerable to bone loss, drank about a quart of either carbonated or non-carbonated mineral water daily for eight weeks. Blood and urine markers for bone turnover showed no difference between the two groups. Sparkling water does not contribute to osteoporosis.
Gas, Bloating, and Acid Reflux
This is where “too much” actually starts to matter. The carbon dioxide dissolved in sparkling water releases gas in your stomach, which can cause bloating, belching, and general discomfort. For most people this is mild and temporary, but if you have a sensitive digestive system or irritable bowel syndrome, it can be genuinely unpleasant.
The bigger concern is acid reflux. When gas builds up in the stomach, it can cause the valve between your stomach and esophagus to relax temporarily, allowing stomach acid to push upward. Research has shown that nearly three-quarters of acid reflux episodes in healthy participants were triggered by belching, and carbonated beverages can increase the frequency of these relaxation events. One study found that carbonated drinks significantly reduced pressure at the lower esophageal valve compared to non-carbonated drinks, making reflux more likely.
If you already have GERD or frequent heartburn, clinicians at UChicago Medicine recommend switching to non-carbonated beverages. Drinking through a straw can make things worse, too, since you tend to swallow more air alongside the carbonated liquid.
How Much Is Actually Too Much
There’s no established upper limit for plain sparkling water in healthy people. The practical ceiling is your own comfort. If you’re drinking several cans or bottles a day and noticing bloating, frequent burping, or a feeling of fullness that keeps you from eating enough, you’re probably overdoing it. Cutting back to a couple of servings a day and drinking still water the rest of the time is a simple fix.
The risks go up if your sparkling water contains added citric acid, sugar, or artificial sweeteners, all of which turn it into a different category of beverage with its own set of concerns. Plain seltzer, club soda, and unflavored sparkling mineral water are the versions that hold up best under scrutiny. Check the ingredients label: if it’s just water and carbon dioxide, you’re in the clear.