The healthiest sparkling water is plain mineral water or unflavored seltzer with no added sugars, sweeteners, or sodium. These options give you the hydration of still water with essentially zero health downsides. But not all bubbly water is created equal. The differences between seltzer, mineral water, club soda, and tonic water matter more than most people realize, and small details like flavoring ingredients and even packaging can shift the health equation.
How the Four Types Compare
Sparkling water is a broad term that covers several distinct products, and they vary in mineral content, sodium, and added ingredients.
- Seltzer is plain water with added carbonation. It contains no added minerals and is sodium-free, making it the simplest option on the shelf.
- Sparkling mineral water comes from a natural spring or well and contains naturally occurring minerals like calcium, magnesium, and sodium. The FDA requires at least 250 parts per million of dissolved solids from the source. An 8-ounce glass typically contains 10 to 30 milligrams of sodium depending on the brand.
- Club soda is carbonated water infused with added minerals like potassium sulfate, sodium chloride, and sodium bicarbonate. It packs about 95 milligrams of sodium per 12-ounce serving, which adds up quickly if you drink several cans a day.
- Tonic water is the outlier. It contains quinine (a bitter compound from tree bark) and is sweetened with sugar or high-fructose corn syrup. A can of tonic water can have as much sugar as a soft drink, so it belongs in the mixer category, not the health drink category.
For everyday drinking, seltzer and mineral water are your best bets. Mineral water has a slight edge because its naturally occurring calcium and magnesium contribute small amounts to your daily intake. Club soda is fine occasionally but less ideal if you’re watching sodium. Tonic water is best avoided as a hydration choice.
What About Flavored Sparkling Water?
Most flavored seltzers use “natural flavors,” which are extracts derived from fruits, spices, vegetables, or other plant sources. These are generally recognized as safe and don’t add calories or sugar. The concern starts when brands add sweeteners. Some flavored sparkling waters contain sucralose, aspartame, or sugar alcohols, which shift the product closer to diet soda territory. Check the ingredients list: if it reads “carbonated water, natural flavor” and nothing else, you’re in good shape. If you see sweeteners, citric acid, or sodium listed, it’s worth comparing brands.
Effects on Teeth
Carbonation creates carbonic acid, which lowers the pH of water. A large study measuring 32 carbonated water brands found an average pH of 5.46, compared to 6.81 for still water. Tooth enamel begins to demineralize below a pH of about 5.2 to 5.5, and 10 of the carbonated brands tested fell below that threshold. Plain sparkling water sits right near the borderline, meaning it has slightly more erosive potential than still water but far less than sodas, fruit juices, or sports drinks, which often have pH values below 3.5.
In practical terms, drinking sparkling water with meals (when saliva production is higher) and avoiding swishing it around your mouth minimizes any risk to enamel. The concern is more relevant for people who sip carbonated drinks continuously throughout the day.
Effects on Bones
The idea that carbonated water weakens bones comes from research on cola, not sparkling water. A study published in the British Journal of Nutrition compared postmenopausal women who drank about a quart of carbonated mineral water daily with women who drank the same amount of still mineral water. After eight weeks, blood and urine markers for bone turnover showed no difference between the two groups. Separate research found that non-cola carbonated drinks had no association with lower bone mineral density. Cola’s link to slightly lower hip density in women likely comes from its caffeine and phosphoric acid, neither of which is present in plain sparkling water.
Digestion and Bloating
Carbonation temporarily expands the stomach with gas, which can cause bloating or discomfort in some people, particularly those with acid reflux or irritable bowel syndrome. A clinical study found that carbonated water didn’t change how fast the stomach emptied food, but it did change where food sat inside the stomach. With carbonated water, a significantly greater proportion of both solids and liquids stayed in the upper stomach compared to still water. This redistribution is likely caused by gas distension pushing food upward.
For most people, this effect is mild and short-lived. Some people actually find carbonated water relieves indigestion symptoms. If you notice consistent bloating or reflux after sparkling water, switching to still water with meals and saving the bubbles for between-meal sipping can help.
PFAS and Contaminants
PFAS, sometimes called “forever chemicals,” have drawn attention in bottled water testing. The FDA tested 197 bottled water samples collected between 2023 and 2024, including purified, spring, artesian, and mineral varieties. Only 10 of those samples had detectable PFAS levels, and none exceeded the EPA’s maximum contaminant levels for drinking water. The FDA did not name specific brands in its report, so choosing a “PFAS-free” brand based on government data alone isn’t currently possible. Independent testing from organizations like Consumer Reports has periodically published brand-level results, which can be worth checking if this is a priority for you.
Does Packaging Matter?
It does, more than most people expect. Research comparing endocrine-disrupting chemicals across packaging types found that beverages in metal cans had higher concentrations of bisphenol compounds (like BPA) than the same beverages from the same manufacturer packaged in glass or plastic. Glass consistently showed the lowest or undetectable levels. If you drink sparkling water daily, choosing glass bottles over cans reduces your exposure to these chemicals. Plastic falls somewhere in between but generally tested lower than cans for BPA specifically.
What to Look For on the Label
The healthiest sparkling water has a short ingredients list. Here’s what to prioritize:
- Ingredients: Carbonated water only, or carbonated water plus natural flavor. No sweeteners, no added sodium.
- Sodium: Under 20 milligrams per serving. Plain seltzer has zero. Mineral water typically has 10 to 30 milligrams per 8 ounces. Club soda runs around 95 milligrams per 12 ounces.
- Sugar: Zero grams. Any sparkling water with added sugar or high-fructose corn syrup (like tonic water) is a different product entirely.
- Packaging: Glass is ideal for minimizing chemical exposure. Cans are convenient but carry slightly higher BPA levels.
Sparkling mineral water from a reputable source, unflavored or flavored only with natural extracts, packaged in glass, is about as healthy as sparkling water gets. But even a basic store-brand seltzer in a can is a perfectly good choice and a significant upgrade over soda, juice, or tonic water for anyone looking to cut sugar without giving up carbonation.