Water Filter vs Purification Tablets: Which Is Better for Your Kit

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 shine in different situations. At EmergencyKitLab UK we’ve tested both formats more times than we can count.

After putting both approaches through camping trips, power cuts and family drills, here’s 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 around 4,000 litres. Simple straw design. Great for grab bags.
• Sawyer Squeeze (£30-40): Filters huge volumes — hundreds of thousands of litres rated. More versatile with squeeze pouches and a gravity setup.

Pros:

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

Cons:

• Does NOT remove viruses (rarely an issue with UK freshwater)
• Can freeze and crack in winter
• Needs backwashing for maintenance
• Bulkier than tablets

Purification Tablets

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

Top picks:

• Aquatabs (£8-12 for 50): Chlorine-based, 30-minute treatment time, neutral taste
• Oasis / chlorine dioxide tablets (£10-15): Effective against a wider range of pathogens, often with a taste-neutralising step

Pros:

• Kills viruses (filters don’t)
• Extremely lightweight and compact
• Long shelf life (3 to 5 years)
• Cheap insurance for any kit

Cons:

• 30-minute wait before drinking
• Slight chemical taste
• Doesn’t remove sediment or turbidity
• Limited supply (one tablet per litre)

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 170 g. Total cost: under £45.

For families sheltering at home during an extended power cut, a gravity-fed filter system is the most practical choice. It processes large volumes without effort — useful if a burst main or local flooding has knocked out your supply.

Use the EmergencyKitLab UK emergency planner to work out exact water needs for your family and get product recommendations tailored to your scenario.

Sources: UK Health Security Agency water guidance, gov.uk emergency water advice, WHO water purification standards