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Testing note: We haven’t hands-on tested these filters. Specs come from LifeStraw’s and Sawyer’s product pages and the Amazon listings, checked Oct 21, 2026. Treatment steps come from the CDC and EPA.
Bottom line: Stored water comes first. A filter is the backup for when it runs low, a well pump has no power, or a boil-water notice drags on. Our pick for a household is the LifeStraw Peak Gravity 8 L with storage bag: hang it, fill it and let gravity do the work. One catch applies to every filter here: none remove viruses or chemicals, so when a notice says to boil or disinfect, do that too.
Our pick
LifeStraw Peak Gravity 8 L + 8 L storage bag: a hanging bag with a 0.2 micron filter that removes bacteria and parasites, rated for up to 500 gallons, plus a second bag to hold the clean water.
Want one small filter for bottles and pots? The Sawyer Squeeze. Need one per person for a go-bag? The LifeStraw Personal.
What a filter can and can’t do
The CDC calls boiling the best way to kill germs, and filtering then disinfecting the next best. A filter with pores of 0.3 micron or smaller removes bacteria and parasites, but not viruses. Bleach kills bacteria and viruses but may not kill parasites like Giardia and Cryptosporidium. That’s why the two work best together (CDC).
Follow your water utility first. If it issues a boil-water or do-not-drink advisory, do what it says (CDC). And no filter, boiling or bleach makes water with fuel or chemicals safe, so skip floodwater and use stored water instead.
Our picks
Our pick: LifeStraw Peak Gravity 8 L with storage bag
A heavy-duty 8 L (about 2 gallon) bag that hangs from a hook, door or cabinet while water drains through a 0.2 micron membrane microfilter. LifeStraw lists it at 99.999999% of bacteria, 99.999% of parasites and 99.999% of microplastics, and says it meets US EPA and NSF P231 standards for bacteria and parasites. The filter lasts up to 500 gallons and stops flowing when it’s used up, so you’re never guessing (LifeStraw). This listing adds an 8 L bag to catch and store the clean water, and the filter also unscrews for use as a straw.
The catch: it doesn’t remove viruses, so disinfect the clean water when a notice calls for it. Amazon showed only a few left when we checked.
Full maker specs: LifeStraw Peak Gravity 8 L
- Filter: Membrane microfilter, 0.2 micron
- Removes: 99.999999% of bacteria; 99.999% of parasites; 99.999% of microplastics, silt, sand and cloudiness
- Standards: Meets US EPA and NSF P231 for bacteria and parasites, per LifeStraw
- Rated life: Up to 500 gallons (2,000 L); flow stops at the end
- Size and weight: 14 × 23.5 in bag; 19 oz; 47 in hose
- In the box: 8 L gravity bag with hose, backwash tool, carabiner, storage cap and strap; the Amazon listing adds an 8 L storage bag
- Storage: For more than a month, LifeStraw says to store the used filter in a saltwater solution so the membrane stays wet
Most versatile: Sawyer Squeeze SP129
A palm-size filter, about 3 ounces, rated 0.1 micron absolute. Sawyer lists 99.99999% of bacteria, 99.9999% of protozoa such as Giardia and Cryptosporidium, and 100% of microplastics. Fill a pouch, screw on the filter and squeeze clean water into a bottle, pot or jug. It also fits standard 28 mm bottle threads and works in a gravity setup (Sawyer). Backflushing restores the flow, and the kit includes two 32 oz pouches.
The catch: it doesn’t remove viruses. Squeezing gallons takes effort, so for a whole household the gravity bag is easier.
Full maker specs: Sawyer Squeeze SP129
- Filter: 0.1 micron absolute hollow fiber membrane
- Removes: 99.99999% of bacteria; 99.9999% of protozoa; 100% of microplastics
- Weight: About 3 oz (filter), per Sawyer
- Fits: Included pouches and standard 28 mm bottle threads; inline or gravity use
- In the box: Filter, two 32 oz pouches, cleaning tools, adapters and a mesh bag, per Sawyer and the Amazon listing
- Warranty: Lifetime limited, per Sawyer
For the go-bag: LifeStraw Personal
A simple drinking straw with no pump or parts. LifeStraw lists 99.999999% of bacteria and 99.999% of parasites, and it lasts up to 1,000 gallons. It’s light enough to keep one per person in each kit, at about 1.6 oz per the Amazon listing (LifeStraw).
The catch: you drink straight from it, so it can’t fill a pot or a baby bottle. It doesn’t remove viruses either.
Full maker specs: LifeStraw Personal
- Filter: Membrane microfilter, 0.2 micron
- Removes: 99.999999% of bacteria; 99.999% of parasites; microplastics down to 1 micron
- Rated life: Up to 1,000 gallons (4,000 L)
- Weight: About 1.6 oz (45 g), per the Amazon listing
- Use: Drink directly from the water; no batteries or parts to replace
Filter, then disinfect
Our water storage guide has the full EPA bleach table. Use only regular, unscented bleach.
Before the next outage
- Store water first. The CDC says at least 1 gallon per person per day for 3 days; our water storage containers make that easier.
- On a well? The pump stops when the power does; see our well pump guide.
- Keep unscented bleach and a dropper with the filter, and check the bleach date.
- Open and read the manual now, not by lantern light.
FAQ
Do water filters remove viruses?
Most portable filters don’t. The CDC says filters with pores of 0.3 micron or smaller remove bacteria and parasites, not viruses. Boil the water, or filter it and then disinfect it with unscented bleach.
Can you use a water filter during a boil-water notice?
Follow the notice. A filter alone doesn’t remove viruses, so boil the water or filter it and then disinfect it, as the CDC advises. Use bottled or stored water if you can’t do either.
What is the best emergency water filter for a family?
A hanging gravity filter is easiest for a household. Our pick, the LifeStraw Peak Gravity 8 L, filters a bag at a time without pumping and is rated for up to 500 gallons.
Do emergency water filters expire?
LifeStraw says its products have no shelf life before first use. Each filter has a rated life: up to 500 gallons for the Peak Gravity and 1,000 gallons for the Personal. After use, follow the maker’s cleaning and storage steps.
Specs checked Oct 21, 2026, from LifeStraw’s and Sawyer’s product pages and the Amazon listings. Treatment steps from the CDC and EPA. We haven’t hands-on tested these filters.