Sparkling or still? That question prefaces any meal in finer sit-down restaurants, and these days the answer seems to be, overwhelmingly, sparkling — and not just when dining out. Sparkling water, also called seltzer, carbonated water, and club soda, has experienced a surge in popularity in recent years that shows no signs of slowing. With an 18 percent annual growth rate between 2020 and 2021, the U.S. market for sparkling water is “one of the fastest growing nonalcoholic beverage categories,” according to Beverage Industry.

Fizzy water may be rising because more people are turning to it as a healthy alternative to soda or booze. Some people don’t love the flavor of tap water or find drinking nothing but plain H₂O all day long boring. Carbonation feels a bit more exciting, and there are countless calorie-free flavors to choose from. But does sparkling water meet your hydration needs the same way still water does? And does it have any side effects other than pure refreshment? Read on to find out.

How Much Hydration Do You Need?

You’re probably aware that staying hydrated is one of the best things you can do for your health. Proper fluid balance is necessary to eliminate waste, protect body tissues, and maintain energy levels, according to Mayo Clinic. And while it may sound easy, a lot of people struggle to chug enough water in a day to keep their bodies functioning optimally.

The precise amount you need varies according to your gender, activity level, and even the climate you live in, so there is no official recommended dietary allowance (RDA) for fluids. The most widely accepted measure comes from the National Academies of Sciences, Engineering, and Medicine, which recommends that women get about 2.7 liters (L) of fluid per day and men get about 3.7 L per day. After deducting the roughly 20 percent of that amount that comes from the food we eat, that leaves approximately nine 8-ounce (oz) cups of liquid a day for women and 13 8 oz cups a day for men.

Water should be your main source of fluids, but does it matter whether that water is bubbly or not? Here's what researchers have determined when it comes to sparkling water and hydration.

Water vs. Sparkling Water: How Do They Compare?

Researchers developed a beverage hydration index (BHI) based on the results of a randomized trial that tested the effects of 13 commonly consumed drinks on the hydration levels of 72 men, all of whom started the experiment in an adequately hydrated state. The results, which were published in March 2016 in the American Journal of Clinical Nutrition, found water and seltzer to be equally hydrating. Those results aren’t too surprising, given that sparkling water is just still water infused with carbon dioxide to make it bubbly, sometimes with added flavor.

While many people find a little fizz and flavor appealing, past research has found that too carbonation can cause bloating and gastrointestinal discomfort because of the air it adds to your gut. So, while sparkling water is good for you, it is still possible to overdo it.

Nutrition Facts for Sparkling Water

Again, because sparkling water is water plus carbonation (gas), it is pretty much identical nutritionally to still water. Apart from a very small amount of sodium some brands add for flavor, per the USDA, it’s zeros across the board: no calories, sugar, or bad stuff. Just keep an eye on the ingredients list, because some brands add fruit juice or puree, while others add sugar or artificial sweeteners. Calories will still be low in all these beverages, but you’ll want to make sure you know exactly what you’re getting in your glass.

Sparkling Water vs. Soda: Which Is More Hydrating?

Hands down, sparkling water is the clear winner here. Most soft drinks have a carbonated water base, but also sugar or artificial sweetener, phosphoric or citric acid to act as preservatives or flavoring agents, and chemicals for color, research shows. Because soda has more of those other ingredients, it has less water — only 89.4 percent water by weight, per USDA data. Sparkling water, on the other hand, is 99.9 percent water by weight, making it far more hydrating. It's also a healthier choice. A single 12 oz can of soda contains nearly 37 grams (g), or almost 9 teaspoons, of sugar, per USDA data. If you are a soda lover, switching out even one can of soda for sparkling water per day can decrease your risk of obesity, type 2 diabetes, and heart disease, according to the Harvard T.H. Chan School of Public Health, without sacrificing the bubbly feel that you love. One 12 oz can of cola, for instance, contains 155 calories, which means a seltzer instead would save you more than 56,000 calories a year. At the same time, you’ll be better hydrated — that’s a win-win.

Are All Kinds of Sparkling Water Equally Hydrating?

Fizzy drinks can go by a host of different names, but they’re not entirely the same. Here are the major differences, and how each kind compares with regular H₂O.

Seltzer, sparkling water These two names are interchangeable and refer to the same product: plain old water with carbonation in the form of added carbon dioxide to give the drink its signature fizz. At 100 percent water, seltzer and sparkling water are just as hydrating as plain, flat water. They do come in flavored and unflavored varieties, but that doesn’t have any effect on how hydrating they are. Just keep an eye out for brands with added sugars and avoid those whenever possible.

Club soda Like seltzer, club soda has added carbon dioxide for bubbles, but club soda also has potassium bicarbonate and potassium sulfate added, notes the Cleveland Clinic. This gives club soda more trace minerals than seltzer, according to the USDA, although its taste and uses are exactly the same as seltzer's. If you’re keeping a close eye on your blood pressure and sodium intake, it’s important to remember that a single 12-ounce can of club soda contains 75 milligrams (mg) of sodium. That’s not a ton, but if you’re sipping club soda all day long, it adds up.

Sparkling mineral water Like club soda, sparkling mineral water has several trace minerals, per the USDA. Because it is made from natural spring or well water, the type and amount of minerals will vary from brand to brand, as will the taste. Sometimes these minerals cause natural carbonation and other times carbon dioxide is added to create an extra fizzy kick.

Don't confuse any of the above beverages with tonic water, which, although also clear and carbonated, is not a sparkling water. Tonic water is made with quinine, which gives it its characteristic bitter flavor, and it's then sweetened with sugar to counteract the bitterness. As a result, tonic water contains about 120 calories per 12 oz can — all of them from added sugar, per the USDA. Tonic water is most often used as a mixer for alcoholic beverages. That’s why it’s best to skip tonic water and opt for any type of sparkling water instead.

Health Benefits of Sparkling Water Beyond Hydration

Since seltzer is just bubbly water, its only real benefit is hydration, but that’s a super important health benefit given that the average American older than 4 is drinking just over 4.5 cups of water per day (well below the recommended amount), according to a study published in November 2020 in Frontiers in Nutrition. In addition, some fortified seltzers, club sodas, and sparkling mineral water brands contain trace amounts of minerals such as calcium and magnesium that count toward your daily value of these nutrients.

Some people wonder if sparkling water is bad for their teeth. Data from the American Dental Association indicates that sparkling water is no more damaging to your teeth than regular tap water and is a healthy addition to your hydration routine.

Tips for Enjoying Sparkling Water to Maximize the Perks

There’s nothing quite like a cold glass of sparkling water on a hot day. It’s refreshing, hydrating, and with the wide variety of flavors to choose from, not boring. And you can always add variety to your routine by stirring in fresh berries, citrus, or mint to lend additional flavor and nutrition to your cup. Adding the juice of one lemon, for instance, will make your seltzer an excellent source of vitamin C, per data from the USDA. Similarly, stirring in (and eating) just 10 raspberries will get you 1.2 g of fiber, notes the USDA. No matter how you enjoy your sparkling water, it will help you meet your hydration goals. Nutritionally, it’s best to choose a brand that doesn’t contain any added sugars or sweeteners. There are many brands to choose from, but if you can’t find the exact flavor you’re hoping for, you could always create your own at home and add it to unflavored sparkling water. If you get really into DIY seltzer, a countertop home carbonation machine might save you money (and trips to the recycling bin or bottle return).

Should You Try Sparkling Water to Stay Hydrated?

Absolutely! Sparkling water is a great addition to any beverage lineup. Free from calories and sugar and as hydrating as still water, seltzer, sparkling water, club soda, and sparkling mineral water are all excellent choices for staying hydrated.

Does Sparkling Water Count as Fluid?