Artesian, spring, purified, and sparkling waters may be treated differently or come from different places.

Sales of bottled water are on the rise, increasing 2 percent, to $7.8 billion, from August 2010 to August 2011 in supermarkets, drugstores, gas and convenience stores, and mass merchants (excluding Walmart), according to SymphonyIRI Group, a market-research company.

If you’re going to pay for a product you could get for free, it helps to know what you’re buying, so below you’ll find a water glossary. Along with the information that follows, note that you may see “glacier water” and “mountain water” on bottles, but there’s no standard definition for those terms.

Whatever the bottle says, don’t be misled by crisp blue labels and pictures of mountains. Forty-seven percent of the bottled water sold in the U.S. is tap water that’s been purified, according to data from the Beverage Marketing Association, a trade group. If you’re concerned about the water quality in your area but don’t want to pay for bottled water, check out our review of water filters.