Quick Answer
Treating water from a snow source is highly recommended to prevent waterborne illnesses. Even with proper snow collection and storage, water can become contaminated with bacteria, viruses, and other pathogens. Boiling or using a water filter is an effective way to make snow water safe for consumption.
Sources of Contamination
Snowmelt can pick up bacteria, viruses, and other pathogens from the surrounding environment. These contaminants can come from animal waste, human waste, and other sources of pollution. In areas with high human activity, such as near trails or campsites, the risk of contamination is even greater. For example, a single gram of human waste can contaminate up to 20 liters of water.
Treatment Methods
Boiling is the most effective method of treating snow water. Bring the water to a rolling boil for at least 1 minute at an altitude of 6,500 feet or lower. For every 1,000 feet above 6,500 feet, add 1 minute to the boiling time. Using a water filter, such as a Sawyer Mini or a LifeStraw, can also be an effective method of treating snow water. These filters can remove bacteria, viruses, and other microorganisms from the water, making it safe to drink.
Storage and Handling
Even with proper treatment, snow water can become contaminated if not stored properly. Use a clean, BPA-free container to store the water, and keep it away from direct sunlight and heat sources. If you plan to store the water for an extended period, consider using a water bottle with a built-in filter or purifier, such as a Grayl or a MSR TrailShot.
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