Photo courtesy of Weil Lifestyle
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Dr. Debunker Online Extra
When—and How—to Purify Your Water Supply
By Andrew Weil, M.D., September 2008
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Q: Should I filter my drinking water?
A: It depends on where you live—and on what’s coming out of your tap besides water. In times past, disease-causing germs were the major worry, but that risk is now low. Today we should be concerned about toxic contaminants such as lead, chemical pollutants called PCBs, agricultural chemicals, and even pharmaceutical drugs.
The bottled-water industry has boomed in response to our fears, but bottled water is expensive, may not be as pure as advertised, and comes in plastic containers that may not be as safe as we thought. A home water-purifying system can be a better, more economical option, but I recommend doing some homework before shopping for one.
First, get your water tested. Although comprehensive testing at a private lab will cost $100 or more, the results may allay any concerns and save you the expense and trouble of installing a purifier. And if they do indicate problems, they will guide you in selecting the right system. The kind you choose depends on the types of toxins in your water.
• Simple countertop or on-faucet filters with cartridges containing floss, activated charcoal, and activated carbon will remove unpleasant odors and tastes from water, including those from residues of chlorine. But most activated-carbon filters will not remove heavy metals or toxic minerals. You must change the cartridges on schedule, before they become inactive—find out how much trouble that is and how much the replacements cost. Also, bacteria can build up in the filters after periods of nonuse. Silver-carbon filters prevent bacterial growth, but they are more expensive. By the way, I consider chlorine toxic and advise not drinking water that tastes of it. But if that is the main problem you have, an activated-carbon filter is all you need.
• Solid-block carbon filters are more effective, especially when paired with another unit containing KDF, a copper-zinc alloy. These systems can fit under the sink and are relatively inexpensive. Again, you need to replace cartridges on schedule, so be sure to check on the cost and ease of doing so.
• Reverse osmosis (RO) systems, another under-the-sink solution, force water through a special membrane that removes toxic metals and minerals, plus organic molecules and bacteria. RO depends on good water pressure to work well. If pressure at your tap is low, filtration will be slow. Unlike other systems, this one wastes a lot of water. In arid areas, such as southern Arizona, where I live, RO should not be used.
• Steam distillers purify water by boiling it and condensing the vapor, leaving most contaminants behind. These devices—which can be as small as a kettle on your countertop—tend to be the most expensive systems, but newer models are more efficient and easy to maintain. Unlike other purifying systems, they use electric power. I rely on a home distiller for my own drinking water.
I do not recommend ion-exchange systems for home use or purifiers that rely only on ultraviolet light. They do not remove many of the contaminants that are of greatest concern.
A pioneer in the field of integrative medicine, Andrew Weil, M.D., is a bestselling author and the editorial director of www.drweil.com.
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