Going to the store to pick up a bottle of water seems like a simple enough task—until you start actually reading the labels and realize that not all bottles of water are made equal. In fact, there are quite a few different types of bottled water in the United States, as regulated by the Food and Drug Administration. These categories of bottled water include spring water, mineral water, purified water, and artesian water. Drinking water is also its own category of bottled water, even though all of these bottles water are, ostensibly, meant for drinking. So what is the difference between spring water and mineral water and all of these other types of bottled water?

The one thing that these bottles of water all have in common is that they're, quite simply, pure water. The FDA's definition of bottled water is "water that’s intended for human consumption and sealed in bottles or other containers with no added ingredients, except that it may contain a safe and suitable antimicrobial agent." So these different categories of bottled water have nothing to do withe the water's safety, purity, quality, or even purpose. Instead, the way in which these categories of bottled water differ has to with with the water's source.

So as the name suggests, spring water is, according to FDA regulations, "derived from an underground formation from which water flows naturally to the surface of the earth at an identified location," called a spring. (It can also be collected from a manmade borehole, but there are other regulations associated with that.)

Mineral water also comes from an underground source that's both geologically and physically protected, but it differs from spring water because mineral water contains a "constant level and relative proportions of minerals and trace elements at the point of emergence from the source." This is why different brands of mineral water each taste a little different; they have a different mix of minerals from their unique source.

Artesian water, also known as artesian well water, is water that comes from a tapped aquifer. "Artesian" actually refers to the natural geological process of pressure that causes water from an aquifer, which is a layer of permeable rock and soil that can store water, to rise to the surface and form a well—not "artisanal."

And though this is cool to know that the water in your bottle comes from some far off well or aquifer, it should also be noted that other types of bottled, drinking water are filled with water straight from municipal taps. That's right: it's tap water that's maybe been further filtered or gone through a process of ozonation, which used ozone gas to disinfect the water with leaving a weird taste. That water is often called purified water, and though you can get it in a little plastic bottle, you could also probably get water that tastes fairly similar from the tap in your own kitchen.