Clean water is the one thing you can't go more than a few days without, and in an emergency your tap may not be an option. The two most common ways to make questionable water safe are a physical filter or chemical purification tablets — and they don't do quite the same job.
A filter physically strains the bugs out as you drink; tablets kill them chemically while the water sits. Which is right for you depends on what's in your water, how fast you need it, and how much weight you're willing to carry.
| Feature | Water Filter | Water Purification Tablets |
|---|---|---|
| What it removes | Bacteria, protozoa (cysts) and sediment; most don't remove viruses | Bacteria, protozoa and viruses (chlorine dioxide) |
| Speed | Instant — drink as you go | 30 minutes to 4 hours to work |
| Weight & bulk | Heavier (50–350g) | Featherweight — a blister pack |
| Taste | No aftertaste | Slight chemical taste (mild with chlorine dioxide) |
| Murky / sediment-heavy water | Handles it well | Struggles — needs pre-filtering through cloth |
| Best for | Everyday hydration, hiking, unlimited refills | Backup, viruses, ultralight kits |
Choose a filter if you'll be drinking regularly from streams or want water instantly with no aftertaste. It's the workhorse for hiking and bug-out bags — refill and drink, no waiting. Just remember most straws and squeeze filters don't stop viruses, which matters more abroad than in the UK.
Choose tablets when weight and simplicity win — they're the size of a plaster pack, kill viruses as well as bacteria, and make a perfect backup if a filter clogs or freezes. The trade-off is the wait and a faint taste. In cloudy water, pre-strain through cloth first.
For most UK preppers the honest answer is both. A filter is your primary — fast, tasteless and endlessly reusable — while a strip of chlorine dioxide tablets weighs nothing and covers you for viruses, murky sources, or the day your filter gives up. Carry the filter for daily use and keep tablets as featherweight insurance.
A pocket-sized straw filter that lets you drink directly from streams, rivers and lakes. No batteries, no chemicals and no moving parts — one of the simplest ways to make untreated water safe when the tap stops running.
A versatile squeeze filter you can use with its pouches, a water bottle or inline on a hydration pack. A refillable workhorse for treating larger volumes than a personal straw.
An all-in-one filter bottle you fill from a tap, river or lake and drink straight from. The simplest option for everyday carry and travel.
Chlorine dioxide tablets that treat questionable water to make it safer to drink. A tiny, long-life backup for when filtering or boiling isn't possible.