Not all bottled water is the same—here’s what you need to know.

Artesian, spring, purified, and sparkling waters can differ in treatment methods and sources. While labels may feature mountains or glaciers, terms like “glacier water” and “mountain water” have no standard definitions.

Bottled water sales are steadily growing, reaching $7.8 billion between August 2010 and August 2011 across major retail outlets (excluding Walmart), according to market research from SymphonyIRI Group.

If you’re paying for something that’s often available for free, it’s worth knowing what you’re buying. Surprisingly, 47% of bottled water sold in the U.S. is simply purified tap water, according to the Beverage Marketing Association.

To make an informed choice, learn about the types of bottled water:

• Artesian water: Comes from a confined aquifer.

• Spring water: Flows to the surface naturally.

• Purified water: Typically tap water filtered through reverse osmosis or distillation.

• Sparkling water: Contains carbon dioxide for fizziness, either naturally or added.

If you’re concerned about your local water quality but want to avoid the cost and waste of bottled water, consider using a reliable water filter instead. It’s a cost-effective and eco-friendly solution that ensures clean, safe drinking water at home.