Always treat drinking water from backcountry sources

Water sources may be contaminated by unseen pollutants. We recommend always treating water before drinking it.

While the clear water in that cold mountain stream may look inviting, there may be a number of harmful parasites or bacteria floating in it. Particularly troublesome is Giardia lamblia, a microscopic parasite that can be found in fresh waters. Ingestion of Giardia causes intestinal discomfort, diarrhea, and cramps that may last several months. To avoid the risk of ingesting this organism, treat all water before drinking it.

Water treatment methods include:

• Water filters. The most convenient method of water treatment is a lightweight filtration system consisting of a pump and filter material capable of trapping Giardia. Though somewhat expensive, the filtration system is an increasingly popular alternative. Read the label to see if the filter is effective against Giardia.
  
• Iodine tablets. Far cheaper, iodine tablets are easy to use, lightweight, and take up hardly any space in a pack. Iodine pill treatment can take 20 minutes or longer, and the pill's effectiveness is lessened in cold or murky water. Read the label to see if the manufacturer guarantees the tablet's effectiveness against Giardia, and follow directions for use. Chemical treatment can give a mild unpleasant taste to the water. If desired, add powdered, flavored drink mix to the water to improve the taste. (Note that iodine can have unwanted health consequences, especially in people with thyroid disease and pregnant women.)
  
• Chlorine treatment. Household bleach can be used to disinfect water. The recommended treatment: Add four drops of bleach (sodium hypochlorite) per quart and let stand for 30 minutes before drinking. Chemical treatment can impart an unpleasant taste to water.
  
• Boiling water. Keep water at a boil for at least one minute (up to five minutes at high altitudes). Boiling water is a reliable method of destroying Giardia.

These filters and chemical treatments can be found at the Pinkham Notch Visitor Center and in outdoor equipment stores.

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