Tongass National Forest

Tongass Home » About the Tongass » Safety

Is The Water Safe?

Don't assume the water is safe to drink. Treat all raw water!

Giardia - A Hidden Hazard

Clear, cold, free-running "natural" water may not be as clean - or as safe - as it looks. Drinking it untreated could result in an intestinal disorder called Giardiasis (gee-ar-dye-a-sis). It can cause you severe discomfort.

The culprit is a microscopic organism, Giardia lamblia, sometimes found in mountain streams and lakes. These natural waters may look, smell, and taste good. You may see wildlife drinking without hesitation from these sources.

Don't assume the water is safe to drink. Giardia may or may not be present, but you should be aware of possible danger.

Giardiasis - Symptoms and Treatment

Although giardiasis can be incapacitating, it is not usually life threatening.

Symptoms may appear a few days to a few weeks after drinking contaminated water and may last up to 6 weeks. They include:

• diarrhea
• increased gas
• loss of appetite
• abdominal cramps
• bloating
• weight loss

Treatment is important. See your doctor. If not treated, the symptoms may disappear on their own, only to recur intermittently over a period of many months. Other diseases can have similar symptoms, but if you have drunk untreated water you should suspect giardiasis and inform your doctor. With proper diagnosis, your doctor can prescribe medication to cure the disease.

Protect Yourself

Treat all raw water. The most certain treatment to destroy giardia is to boil water for at least 3 minutes. Boiling will also destroy other organisms causing waterborne disease. At high altitudes, you should maintain the boil for 5 minutes for an added margin of safety.

Chemical disinfectants such as iodine or chlorine tablets or drops are not considered as reliable as heat in killing giardia, although these products work well against most waterborne bacteria and viruses that cause disease. In an emergency where chemical disinfection is necessary, use an iodine-based product, since iodine is often more effective then chlorine. If possible, filter or strain water first, and then allow the iodine to work at least 30 minutes before you drink the water. If the water is cold or cloudy, wait at least an hour, or use more iodine.

For short trips, take a supply of water from home or other domestic source.

Protect Others

Giardia can be readily transmitted between humans and animals. Feces (human and animal waste) can contain the organism. Bury all waste 8 inches deep and at least 100 feet from natural waters.

Dogs, like people, can get infected with giardiasis. They can contaminate the water and continue the chain of infection from animals to humans. For their sake and yours, consider carefully before bringing your canine friends along.

USDA Forest Service - Tongass National Forest
Last Modified: September 01, 2006