Best water filters and purifiers for emergencies (2026)
When the tap stops or a boil-water notice goes out, the CDC says boiling is the best way to kill germs: a rolling boil for 1 minute, or 3 minutes above 6,500 feet. A filter is the backup for when you can't boil, and the light option for a go-bag. Here they are compared on what each maker says it removes.
By PreparedStates editors · Updated October 22, 2026 · 6 products, 2 of 6 price-tracked
Our picks
LifeStraw Family
Household gravity purifier that handles viruses
Sawyer Squeeze
The most versatile filter
All 6 compared
| Filter | Removes (maker's claim) | Filter life | Price |
|---|---|---|---|
Bacteria, protozoa, cysts, sediment The most versatile filter | Bacteria, protozoa, cysts, sediment | — | |
Our verdictOur verdictResearched Squeeze from a pouch, drink inline or set it up as a gravity filter: a 0.1-micron filter that handles bacteria and protozoa. Doesn't claim to remove viruses, so boil or disinfect water from flooding or sewage. Best for The most versatile filter Good
Worth knowing
Who shouldn't buy it: Don't buy it if your water may carry viruses (floodwater): boil it instead. | |||
Viruses, bacteria, parasites, microplastics Household gravity purifier that handles viruses | Viruses, bacteria, parasites, microplastics | — | $63 at LifeStraw Checked Oct 22In stockCheck price → |
Our verdictOur verdictResearched A gravity unit that treats water for the whole household and, per LifeStraw, removes viruses as well as bacteria and parasites. The pick if you'd rely on a filter at home. Best for Household gravity purifier that handles viruses Good
Worth knowing
Who shouldn't buy it: Don't buy it if you need something for a pocket or go-bag. | |||
4.0 | Viruses, bacteria, protozoan cysts | — | $99.95 at Grayl Checked Oct 22In stockCheck price → |
Our verdictOur verdictResearched A press bottle that, per Grayl, removes viruses, bacteria and protozoa in one go: the portable choice if you want virus protection away from home. Pricey, and cartridges need replacing. Best for Personal purifier for a go-bag Good
Worth knowing
Who shouldn't buy it: Don't buy it if budget matters: a Sawyer plus boiling costs far less. | |||
4.0 | Bacteria, parasites | 1,000 gal | |
Our verdictOur verdictResearched Drink straight from a water source through it: 1,000 gallons of filter life for bacteria and parasites. A sensible extra for each go-bag, not a household system. Best for Cheap, light backup for every bag Good
Worth knowing
Who shouldn't buy it: Don't buy it if you need to treat water for a family. | |||
Bacteria, protozoa · 100,000 gal Smaller, cheaper Squeeze | Bacteria, protozoa | 100,000 gal | |
Our verdictOur verdictResearched The Squeeze's little sibling: same 0.1-micron idea, smaller and cheaper, with Sawyer's 100,000-gallon rating. Slower flow than the Squeeze. Best for Smaller, cheaper Squeeze Good
Worth knowing
Who shouldn't buy it: Don't buy it if you'll filter a lot of water daily: the Squeeze flows faster. | |||
3.5 | 0.1-micron hollow-fiber filter | — | |
Our verdictOur verdictResearched A collapsible 1-liter bottle with a 0.1-micron hollow-fiber filter; folds flat in a bag. The listing doesn't claim virus removal. Best for Fastest-flowing soft bottle Good
Worth knowing
Who shouldn't buy it: Don't buy it if you want something that lasts years of rough use. | |||
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Before you buy
Filters and purifiers do different jobs.
The Sawyer, LifeStraw Personal and Katadyn filters here are built for bacteria and parasites. LifeStraw Family and Grayl say they also remove viruses, which matters more for flood or sewage-contaminated water.
The CDC says chemical disinfectants (bleach, iodine, chlorine dioxide) kill viruses and bacteria but may not kill parasites, so a filter plus disinfection covers more than either alone.
Cloudy water clogs filters fast.
The CDC suggests letting it settle or straining it through a clean cloth or coffee filter first.
Filter life varies from 1,000 gallons (LifeStraw Personal) to Sawyer's 100,000-gallon rating for the MINI.
For a household, a gravity unit saves a lot of squeezing.
We verify every product's specifications against at least two independent sources, re-check its US price and stock on a schedule where we can track it automatically, and cross-check safety-relevant claims against official guidance. Every review is labelled Researched or Used and reviewed by us: where we've bought a product, or been sent it free, and used it ourselves, its review says which; where we haven't, our verdict is a considered spec-and-evidence comparison, not a hands-on test — and commissions never change a ranking either way. Read our full methodology →
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Common questions
Do water filters remove viruses?
Most portable filters don't claim to. Of the products here, LifeStraw Family and Grayl GeoPress say they remove viruses; the Sawyer, LifeStraw Personal and Katadyn filters are made for bacteria and parasites.
Is boiling better than filtering?
The CDC says boiling is the best way to kill germs: a rolling boil for 1 minute, 3 minutes above 6,500 feet. A filter is useful when you can't boil, or to clear sediment.
Will a filter make floodwater safe?
Not reliably. Floodwater can carry viruses and chemicals that these filters don't remove. Use stored water and follow local notices.
What's the best water filter for a family?
A gravity unit like LifeStraw Family treats water for several people without squeezing, and says it removes viruses as well.