Purifying water makes packing huge amounts of water with you unnecessary.
Rainwater collected in clean containers or in plants is usually safe for drinking. However, purify water from lakes, ponds, swamps, springs, or streams, especially the water near human settlements or in the tropics.
When possible, purify all water you got from vegetation or from the ground by using iodine or chlorine, or by boiling.
Purify water by:
Using water purification tablets. (Follow the directions provided.)
Placing 5 drops of 2 percent tincture of iodine in a canteen full of clear water. If the canteen is full of cloudy or cold water, use 10 drops. (Let the canteen of water stand for 30 minutes before drinking.)
Boiling water for 1 minute at sea level, adding 1 minute for each additional 300 meters above sea level, or boil for 10 minutes no matter where you are.
By drinking non-potable water you may contract diseases or swallow organisms that can harm you.
Examples of such diseases or organisms are:
Dysentery. Severe, prolonged diarrhea with bloody stools, fever, and weakness.
Cholera and typhoid. You may be susceptible to these diseases regardless of inoculations.
Flukes. Stagnant, polluted water–especially in tropical areas–often contains blood flukes. If you swallow flukes, they will bore into the bloodstream, live as parasites, and cause disease.
Leeches. If you swallow a leech, it can hook onto the throat passage or inside the nose. It will suck blood, create a wound, and move to another area. Each bleeding wound may become infected.