Turns out, bottled water companies aren’t just trying to confuse the average H2O guzzler by plastering their bottles with labels like “Mineral,” “Alkaline,” and “Artesian.”
This simply means the bottled water has a slightly higher pH than other forms. You may recall from chemistry class that the pH scale measures how acidic or alkaline a substance is. On a scale from zero to 14, any pH below seven indicates a substance is acidic (vinegar hovers around two or three). On the other hand, anything above seven indicates a substance is alkaline (ammonia is around 11 or 12). Seven—which is the typical pH of tap water—is neutral. Most bottled waters are slightly acidic (pH below seven), while alkaline waters hover around eight or nine, Sollid says.
In order to classify as “mineral water,” the H2O must come from an underground source and contain at least 250 parts-per-million of total dissolved solids like zinc, iron, and chloride, Sollid says. However, none of these minerals or trace elements can be added in—they must occur naturally.
That said, mineral quantities vary widely among tap and bottled water, and both water sources may contain high levels of calcium, magnesium, and sodium, according to research published in the Journal of General Internal Medicine. In fact, half of the tap water sources analyzed would provide between eight and 16 percent of your daily recommended intake (RDI) of calcium and between six and 31 percent of your RDI of magnesium if you drink two liters per day. So, buying a pricey bottle of mineral water doesn’t guarantee you’re getting more minerals than tap water.
Sounds fancy, but Sollid says “artesian” simply means the water was collected from a well that taps into an aquifer, or underground permeable rock. In fact, artesian water is no different from other bottled water taken from springs, says the scientific agency U.S. Geological Survey.
While artesian water companies like VOSS and Nakd claim that drinking their water will help you fight colds, improve concentration and keep skin youthful, there’s no research to support these benefits.
“The only difference between artesian water and tap water is the cost,” Sollid says.
What Does This Mean for Tap Water?
According to Sollid, the only real differences between bottled and tap are in sourcing and delivery. Tap water comes from public water systems, while bottled water sources vary and are delivered in sanitary, sealed containers.
No matter what kind of water you drink, be sure to drink plenty of it throughout the day. As a rough guideline, the IFIC Foundation suggests that adults down nine to 13 8-ounce glasses of water per day. Keep in mind that you may need more or less according to your activity level.
Good old-fashioned H20 is always your best bet to stay hydrated, but foods high in water content, like watermelon, strawberries, celery, cucumbers, as well as other beverages like tea, smoothies, and juice will also contribute to your daily water needs.