Acquiring clean, safe water is essential when backpacking, hunting, or fishing in remote wilderness areas. In today's post we'll explore some different options for water filtration and purification.
Why You Always Need to Treat Your Water
No matter how pristine the alpine lake or flowing stream may seem, it can still harbor harmful contaminants such as:
- Protozoa – Giardia, Cryptosporidium
- Bacteria – E. coli, Salmonella
- Viruses – Hepatitis A, Norovirus
Generally, the further you are from human activity or livestock, and the closer to a water source (like a spring), the safer the water. But even then, always treat your water before drinking it!
The 3 Main Methods of Water Treatment in the Backcountry
There are three primary ways to make water safe for consumption:
- Filtration
- Chemical Treatment
- UV Sterilization
Yes, boiling is an option in cold weather base camps where a fire is going. This article focuses on commercial options.
1. Water Filters: Fast, Effective, and Easy to use
Filters are the most common method of backcountry water treatment. They work by physically removing protozoa and bacteria through a filter. Some higher-end filters also remove viruses and heavy metals, making them technically "purifiers."
Types of Filters:
- Squeeze filters (e.g., Sawyer Squeeze)
- Pump filters (e.g., MSR Guardian)
- Gravity systems (e.g., Platypus GravityWorks)
- All-in-one bottle filters (e.g., Grayl Geopress)
Pros:
- Immediate access to clean water
- Removes protozoa and bacteria
- Some models remove viruses and heavy metals
Cons:
- They are susceptible to freezing - which damages filter fibers
- Require occasional back-flushing to maintain flow rate
Tip: If it’s below freezing, keep in your sleeping bag or jacket pocket overnight.
2. Chemical Treatments: A Lightweight Backup
Chemical treatments kill bacteria, protozoa, and some viruses, but they don't remove anything. Water will still contain sediment, bugs, and other "floaties" unless pre-filtered through a cloth or mesh.
Types:
- Chlorine Dioxide Drops or Tablets (e.g., Aquamira)
- Iodine Tablets (e.g., Potable Aqua)
Pros:
- Ultralight and compact
- Great as a backup
- No moving parts or maintenance
Cons:
- Wait time: 15 minutes to 4 hours depending on pathogens
- Doesn’t remove sediment or debris
- Can leave a chemical aftertaste
Tip: Combine with a pre-filter (bandana, pantyhose) for better results.
3. UV Light Purifiers: Solid Option for Cold Weather
UV devices (like the SteriPen) kills bacteria, protozoa, and viruses with ultraviolet light.
You simply insert the purifier and agitate the water for a prescribed duration and voila, clean water ready to drink.
Pros:
- Treats all major waterborne pathogens
- Water is ready to drink within minutes
- You don't have to worry about it freezing
Cons:
- It runs on batteries (which are also influenced by very cold weather)
- Doesn’t remove "floaties" or sediment
- They can be finicky
Tip: If water is murky, pre-filter it before using UV light.
Quick Comparison of Water Filtration Options
| Method | Kills Protozoa/Bacteria/Viruses | Removes Sediment | Time to Treat | Weight | Reliability |
|---|---|---|---|---|---|
| Filter | ✅✅✅* (some models) | ✅ | Immediate | Moderate | High |
| Chemicals | ✅✅✅ | ❌ | 15 min – 4 hrs | Ultra-light | Very High |
| UV Light | ✅✅✅ | ❌ | 1–2 min | Light | Medium (battery) |
Final Thoughts: Choose The Right Tool for the Job
For solo trips in warmer weather it's hard to go wrong with a Sawyer Squeeze.
For group trips or base camps with multiple people. A larger gravity fed filter is a great option.
If you're doing a cold weather hunt or backcountry ski trip then a UV purifier is proably the best option unless you plan on boiling at camp.
The old military adage "One is none, and two is one" definitely applies here. A backup is always a good idea. I like Aqua Mira for this if I'm solo.
FAQs
Q: Can I rely on just a filter for virus protection?
A: Only if it’s rated to remove viruses (e.g., Grayl Geopress, MSR Guardian). Otherwise, supplement with chemical or UV.
Q: What’s the best water filter for freezing temps?
A: None. All membrane filters are vulnerable to freezing. Keep it warm or switch to chemical tablets.
Q: Is boiling still a legit option?
A: Yes, it kills everything, but it’s slow, fuel-hungry, and requires an all metal pot ideally with a bailing style handle.