You know, the other day I was looking at some things in the grocery store.

Specifically, water bottles.

Pretty dumb, right? Well, not really.

Because all bottled "water" is not alike. In fact, some of the bottled water sold contains a lot more than just water.

What kind of things? Potassium chloride. Or added sodium.

One major brand was even found to be taking tap water (yes, the stuff you get by turning on the faucet in the kitchen), bottling it, after "purifying" it, and adding a few minerals.

The lesson here? Read what's on the bottle. Know what you're getting.

Here are the classifications the FDA uses for bottled water:

* Artesian well water. Water from a well that taps an aquifer--layers of porous rock, sand and earth that contain water--which is under pressure from surrounding upper layers of rock or clay. When tapped, the pressure in the aquifer, commonly called artesian pressure, pushes the water above the level of the aquifer, sometimes to the surface. Other means may be used to help bring the water to the surface.

According to the EPA, water from artesian aquifers often is more pure because the confining layers of rock and clay impede the movement of contamination. However, despite the claims of some bottlers, there is no guarantee that artesian waters are any cleaner than ground water from an unconfined aquifer, the EPA says.

* Mineral water. Water from an underground source that contains at least 250 parts per million total dissolved solids. Minerals and trace elements must come from the source of the underground water. They cannot be added later.

* Spring water. Derived from an underground formation from which water flows naturally to the earth's surface. Spring water must be collected only at the spring or through a borehole tapping the underground formation feeding the spring. If some external force is used to collect the water through a borehole, the water must have the same composition and quality as the water that naturally flows to the surface.

* Well water. Water from a hole bored or drilled into the ground, which taps into an aquifer.

Personally, I think that bottled water -- while convenient for those times when you're on the run -- is often silly and expensive. Especially if you're drinking it at home. What comes from the tap is -- in most locations -- quite pure, and usually tastes pretty good, too. But if you want bottled water, or need it for any variety of reasons, read and heed what you are getting for your money. Not to mention your health.

Jim Huffman, RN specializes in natural and alternative healing therapies. His first book is 'Dare to Be Free: How to Get Control of Your Time, Your Life, and Your Nursing Career,' and is aimed at helping other nurses find satisfying, dynamic careers. His website is http://www.NetworkForNurses.com and his health blog is at http://www.shababa.blogspot.com