Sales of bottled water are higher than ever, with U.S. per capita consumption increasing from 31 gallons in 2012 to more than 43 gallons in 2019. People choose bottled water for many reasons—because they prefer the taste, believe it’s healthier or safer than tap water (not true in most cases), or just find it convenient.
All bottled water is regulated by the FDA for safety, with standards of identity defining specific types (as described below). But with shelves at grocery stores, drugstores, and other retail outlets overflowing with all kinds of bottled waters, it can be confusing to know how they differ.
Here’s a look at several types:
- Spring water. Water from a natural spring is collected from the site where it bubbles to the surface, or a borehole can be used to tap the underground source of the spring. The key is that the spring must flow naturally; no force must be used to improve or enhance the flow. After any treatment (which includes different steps depending on the manufacturer, such as different filtration processes), the water must contain the same mineral content as the original spring water.
- Mineral water. This water comes from an underground source (such as a spring or a well) that naturally contains a consistent concentration of dissolved minerals—a total of at least 250 parts per million (ppm). Minerals are not allowed to be added. If the water contains more than 1,500 ppm of total dissolved minerals, it’s considered to have a high mineral content. If it contains 250 to 500 ppm, it’s considered to have a low mineral content. But the kinds of minerals, and the amounts, in bottled water vary. For example, the USDA reports one brand as having 119 milligrams of calcium (a good amount), 33 milligrams of magnesium (also good), and 40 milligrams of sodium in a 330-ml (11-ounce) bottle; others have about 60 milligrams of calcium. Mineral waters may be still or bubbly (either naturally or with added carbon dioxide).
- Sparkling water. Sparkling water naturally contains carbon dioxide and can be sourced from a well or spring. Some mineral waters can thus be labeled “sparkling mineral water.” If carbon dioxide was lost during production, it can be added back, but not in greater amounts than it originally had. In contrast, seltzer water, club soda, and tonic water have carbon dioxide artificially added (to regular water) and are regulated by the FDA as soft drinks, not sparkling waters. Tonic water contains bitter-tasting quinine (a chemical originally derived from cinchona tree bark that has been used in high amounts to treat malaria), and it is sweetened, either with some type of sugar or sugar substitute. Club soda (also called soda water) has mineral salts, such as sodium bicarbonate and potassium sulfate, added to make it more alkaline (some people like that taste), which is why these waters have about 75 to 90 milligrams of sodium per 12-ounce bottle.
- Purified water. Purified water has been treated to remove a variety of impurities, such as chemical contaminants, lead, and bacteria, as well as iron, nitrates, sulfates, and bicarbonates. It must contain no more than 10 ppm of dissolved solids. Sourced from a well, spring, or—more commonly than you may think—a municipal water supply (that is, tap water), the water may be processed by different methods (and labeled accordingly), such as distillation (water is boiled, then the steam condenses and is captured), reverse osmosis (a semipermeable membrane is used), or deionization (a process in which charged mineral particles, called ions, are removed). Some minerals may be added back for better taste. Dasani and Aquafina are two major brands that simply treat tap water.
- Artesian (well) water. Regular well water comes from a tapped aquifer—a porous rock, clay, or sand through which water flows. Water in many of the country’s municipal or community water systems (whether public or private) comes from these sorts of wells. Artesian well water is basically well water, except the artesian well taps a confined aquifer, meaning that the aquifer is surrounded by layers of bedrock or clay, which puts pressure on the water. The pressure forces the groundwater up toward the surface via the well. Artesian well water has a greater mineral content than regular well water, giving it a slightly different flavor.
BOTTOM LINE: Grabbing a bottle of water when you’re on the go is okay on occasion, but we don’t recommend you make a habit of it, because of the plastic waste it creates and the large amount of energy that goes into its production and transport—not to mention the unnecessary cost, especially of the trendier waters. Also, bottled waters may not have the levels of fluoride needed to protect teeth; many have none at all because the fluoride is filtered out. Don’t drink bottled waters for the vitamins or minerals they may contain (either naturally or added), or the “extra oxygen” or lower acidity—they are not going to make you healthy, boost immunity or energy, or relax you, despite any claims.
If your home water is not safe to drink, investing in a home treatment system is cheaper than buying bottled water over the long-term—and better for the environment. Want a flavor booster? Try a slice of lemon or lime, or a small amount of your favorite juice, in a glass of tap water. If you want your water carbonated, you can also invest in a home carbonation machine.
These three types of water are an ongoing—and gimmicky—trend:
- Functional (or enhanced) water. Amino acids, vitamins, minerals, herbs, caffeine, raw fruits or vegetables, or other supplemental ingredients are added. But there’s no need for functional waters. A bottle of VitaminWater (from Coca-Cola), for example, contains 150 percent of the daily recommended amount of vitamin C, 100 percent of the recommended amounts of various B vitamins, and 25 per- cent of the recommended amount of zinc—amounts you can easily get from food. A bottle of so-called protein water, typically containing whey protein isolate, may contain 15 to 20 grams of protein (and often added sugar), but the typical American diet already provides more than enough protein.
- Alkaline water. This water contains natural or added minerals (such as calcium, magnesium, and potassium) and may also have acidic ions removed, to achieve an acid-base balance (pH) above 7, meaning that the water is alkaline. Water normally is neutral, with a pH of 7. Proponents claim that consuming too much acidic food compromises health and that drinking water that’s alkaline can prevent or cure diseases. Though there’s a kernel of truth to the idea that a diet that results in a more acidic environment in the body can cause bones to release calcium (thus possibly contributing to bone loss), this is unlikely to be an important effect, especially if you consume adequate calcium. More to the point, there’s no evidence that drinking such water has any significant impact on the acid-base balance of your body; the body has many mechanisms to maintain a normal pH range in the blood. In any case, anything you consume is acidified in the stomach, and that would be the end of any alkalization from such water.
- Super-oxygenated water. These waters claim to have more oxygen than ordinary waters, a result of different proprietary methods, including putting the water under pressure, which forces more oxygen to dissolve in it. This extra oxygen supposedly improves heart function, among other claimed benefits, and is even said to fight wrinkles and hair loss. But this is nonsense. The added oxygen doesn’t add up to anything, since oxygen doesn’t readily cross into the blood through the intestines. Rather, in order to get oxygen, you have to breathe it. And in a healthy person, blood is already highly saturated with oxygen. Besides, as soon as the top is popped on the bottle, the oxygen, which is poorly soluble in water and only held there under pressure, gets released into the air. Any that remains might end up in your stomach where the main effect will be an expensive belch. There is no credible published research—or logical rationale—to back any health benefits, beyond the hydration the water provides, including no evidence of significant improvements in exercise performance.
