Waterborne illness can ruin a trip or worse. Understanding your water treatment options helps you choose the right method for your hiking style and conditions.
What's in the Water?
| Threat | Size | Concern Level |
|---|---|---|
| Protozoa (Giardia, Crypto) | Large | High |
| Bacteria (E. coli, Salmonella) | Medium | Medium |
| Viruses | Tiny | Low (in North America) |
| Sediment | Varies | Clogs filters |
In North America, protozoa are the primary concern. Viruses are rare except in areas with human waste contamination.
Treatment Methods Compared
| Method | Weight | Speed | Effectiveness | Cost |
|---|---|---|---|---|
| Squeeze filter | 3 oz | Fast | Protozoa + bacteria | $25-40 |
| Gravity filter | 8-11 oz | Slow (hands-free) | Protozoa + bacteria | $70-100 |
| UV (SteriPen) | 3-5 oz | Fast | Everything | $80-130 |
| Chemical (Aquamira) | 3 oz | 30 min wait | Everything | $15 |
| Chemical (tablets) | 1 oz | 30-240 min | Varies | $10 |
| Boiling | Cook kit | 5+ min | Everything | Free |
Filters
Squeeze Filters (Sawyer, Katadyn BeFree)
Pros:
- Fast and easy
- No wait time
- Long lasting (some are lifetime)
- Light and compact
Cons:
- Can clog with dirty water
- Don't remove viruses
- Can freeze and break
Best for: Most North American backpacking
Gravity Filters
Pros:
- Hands-free operation
- Great for groups
- High volume
Cons:
- Heavier
- Slow
- More expensive
Best for: Groups, base camping
UV Treatment (SteriPen)
Pros:
- Kills everything including viruses
- Fast (90 seconds)
- No filter to clog
Cons:
- Requires batteries
- Doesn't remove sediment
- Can break
- Must be thorough (clear water only)
Best for: International travel, virus-prone areas, those who want redundancy
Chemical Treatment
Aquamira (Chlorine Dioxide)
Pros:
- Kills everything
- Lightest option
- Improves questionable taste
- Great backup
Cons:
- 30 minute wait time (4 hours for Crypto)
- Requires measuring and mixing
- Chemical taste
Best for: Backup method, ultralight priority
Iodine Tablets
Pros:
- Cheapest option
- Very light
Cons:
- Taste is terrible
- Doesn't kill Cryptosporidium
- Not for pregnant women or thyroid issues
Best for: Emergency only
Recommended Setups
| Hiker Type | Primary | Backup |
|---|---|---|
| Weekend warrior | Squeeze filter | None needed |
| Thru-hiker | Squeeze filter | Aquamira |
| International | UV + filter | Aquamira |
| Ultralight | Aquamira | None |
Pro Tips
- Pre-filter muddy water through bandana
- Let sediment settle before treating
- Backflush filters regularly
- Carry backup on remote trips
- Collect water upstream from trail crossings