Boiling water for five minutes is the best protection against Cryptosporidium. But that’s a hassle. The following compa­nies make products that can filter Crypto: Cuno, Inc. (203.237.5541), Everpure (800.323.7873), Multi-Pure (800.874.7873), Pura (800.382.3252), Sierra Pure (612.423.9732), Peterman Principle (312.540.0220) and Watts Regulator (508.688.1811). Make sure you ask for a filter that is certified “NSF Standard 53 Cyst Removal.” (If it says only “Standard 53,” it cannot stop Crypto.) The Brita Water Filter System does not remove Crypto.

For a free brochure regarding bot­tled water. call the International Bottled Water Association at 800.WATER.11. The IBWA represents most bottlers that sell in the United States and requires members to undergo annual plant inspections by an independent organization. Call the EPA Safe Drinking Water Hotline at 800-426-4791 for questions about your city’s water supply.