Getting sick in the backcountry is more than just inconvenient; it can be dangerous. One of the easiest ways to sideline yourself is by drinking untreated water. Giardia, Cryptosporidium, and bacteria are common threats in seemingly pristine water sources. Understanding your options for water treatment is fundamental to a safe trip.
Filters and Purifiers
Water filters work by physically removing contaminants. The effectiveness depends on the pore size of the filter. Microfilters, generally with pore sizes around 0.1 to 0.2 microns, excel at removing bacteria and protozoa like Giardia and Crypto. Viruses, being much smaller, typically pass through microfilters. For virus removal, you need a water purifier, which often employs a combination of filtration and chemical treatment or a much finer filter.
Pros of Filters:
- Immediate Water: Drink almost instantly after filtering.
- Taste: Generally good, as sediment and organic matter are removed.
- No Chemicals: Ideal for those who prefer to avoid chemical aftertastes.
Cons of Filters:
- Weight & Bulk: Can be heavier and bulkier than chemical options.
- Clogging: Turbid water can quickly clog filters, requiring backflushing or cleaning.
- Freezing: Many filters can be damaged if frozen with water inside.
- Virus Ineffectiveness: Most common backcountry filters do not remove viruses.
Tips for Using Filters:
- Always filter from the cleanest possible source to extend filter life.
- Know how to backflush or clean your filter in the field.
- Consider a pre-filter to remove larger debris.
- Protect your filter from freezing temperatures.
Chemical Treatment
Chemical treatments involve adding substances to water that kill or neutralize microorganisms. The two most common types are iodine and chlorine dioxide. Both are effective against bacteria and viruses. Chlorine dioxide is generally preferred as it's effective against Cryptosporidium and doesn't leave as strong an aftertaste as iodine.
Pros of Chemical Treatment:
- Lightweight & Compact: Often the lightest and most packable option.
- Effective Against Viruses: Both iodine and chlorine dioxide kill viruses.
- No Freezing Risk: Chemicals are unaffected by freezing.
Cons of Chemical Treatment:
- Wait Time: Requires a waiting period (typically 15 minutes to 4 hours, depending on the chemical and water temperature) before water is safe to drink.
- Taste: Can leave an unpleasant chemical taste, especially iodine.
- Limited Shelf Life: Chemical agents can degrade over time once opened.
Tips for Using Chemical Treatment:
- Always follow the manufacturer's instructions for dosage and wait times.
- Consider using a flavored drink mix to mask any chemical taste.
- Note the expiration date and replace old chemicals.
- Warm water can accelerate the treatment process.
Boiling
Boiling water is the oldest and arguably most reliable method of water purification. Bringing water to a rolling boil for one minute is sufficient to kill all pathogens, including bacteria, viruses, and protozoa, at elevations up to 6,500 feet. At higher altitudes, boil for three minutes.
Pros of Boiling:
- 100% Effective: Kills all waterborne pathogens.
- No Equipment Besides a Pot/Stove: Already part of most backpacking kits.
- No Taste: Leaves no chemical aftertaste.
Cons of Boiling:
- Fuel Consumption: Requires significant fuel, especially for large volumes or at high altitudes.
- Time-Consuming: Waiting for water to boil and then cool down.
- Can Be Impractical: Not ideal for quick hydration stops.
Tips for Boiling Water:
- Collect water and bring it to a rolling boil for at least one minute (three minutes above 6,500 feet).
- Consider using a bandana or cloth to pre-filter turbid water before boiling to improve clarity.
- Allow boiled water to cool before drinking to avoid burns.
- Account for extra fuel in your packing plan if boiling is your primary method.
Choosing Your Method (or Methods)
The best water treatment method often isn't just one method. Many experienced backpackers carry a primary method (like a filter) and a backup (like chemical tablets). Your choice will depend on factors like trip duration, location, water source clarity, group size, and personal preference for weight versus convenience.
For example, if you're on a multi-day trip with reliable water sources, a lightweight filter might be your primary. If you're heading to areas known for viruses, or if you want a reliable backup, chlorine dioxide tablets are a smart addition. For minimalist trips or when fuel isn't a major concern, boiling is always a safe bet. Plan ahead, understand your environment, and ensure you have a dependable way to make water safe to drink. Your health in the backcountry depends on it.