Water Filter vs Purification Tablets: Which Is Better for Emergencies?

When your stored water runs out during an emergency, you need a way to make unsafe water drinkable. The two main options are portable water filters and purification tablets. Both work, but they solve different problems and excel in different situations.

After testing both approaches during camping trips, power outages, and family drills, here is our honest comparison.

Portable Water Filters

What they do: Physically strain out bacteria, protozoa, and sediment by forcing water through a membrane with microscopic pores (typically 0.1 or 0.2 microns).

Top picks:

• LifeStraw Personal ($15-20): Filters 1,000 gallons. Simple straw design. Great for go-bags.
• Sawyer Squeeze ($30-40): Filters 100,000 gallons. More versatile with squeeze bags and gravity setup.

Pros:

• Instant clean water, no waiting
• No chemical taste
• Removes turbidity (cloudy water looks and tastes clean)
• Reusable for thousands of gallons

Cons:

• Does NOT remove viruses (rarely an issue in US tap/freshwater)
• Can freeze and crack in winter
• Needs backflushing for maintenance
• Bulkier than tablets

Purification Tablets

What they do: Chemical treatment (typically chlorine dioxide or iodine) that kills bacteria, viruses, and protozoa in water.

Top picks:

• Aquatabs ($8-12 for 50): Chlorine-based, 30 minutes treatment time, neutral taste
• Potable Aqua ($10-15): Iodine-based with taste neutralizer tablets included

Pros:

• Kills viruses (filters do not)
• Extremely lightweight and compact
• Long shelf life (3-5 years)
• Cheap insurance for any kit

Cons:

• 30-minute wait time before drinking
• Slight chemical taste (especially iodine)
• Does not remove sediment or turbidity
• Limited supply (one tablet per liter)

Our Recommendation

Carry both. A filter for daily use and tablets as backup. Your primary should be a Sawyer Squeeze or LifeStraw for their capacity and convenience. Tuck a pack of Aquatabs into your kit as insurance. Total weight: under 6 oz. Total cost: under $50.

For families sheltering at home during an extended outage, a gravity-fed filter system is the most practical choice. It processes large volumes without effort.

Use our emergency planner to calculate exact water needs for your family and get product recommendations tailored to your scenario.

Sources: CDC Water Treatment Guidelines, EPA Emergency Water Disinfection, WHO Water Purification Standards