I'm thinking ahead to our next earthquake
December 9, 2022 12:12 PM   Subscribe

What's the best drinking water filtration/purification system for a small family that can be stored where it will freeze?

We have a summer solution covered, but winter makes this harder to figure out. It freezes and stays frozen here at least 4 months of the year, with a month either side of freeze-thaw cycling.

We have some liquid emergency water, but we don't have the space to keep enough water inside where it won't freeze. We have a camp stove and a grill both with fuel so we can melt ice and snow, but then obviously we have to treat the water... how?

I've heard filters like Lifestraws and similar are damaged by residual water in the filter freezing and thawing, so I was thinking Aquatabs? Or is there a better way?

The city lost power but not water in the last bad earthquake-- but we're on a well with an electric pump now. I gather the landlord has a generator but I kind of want to be belt-and-suspenders about water.
posted by blnkfrnk to Food & Drink (7 answers total) 6 users marked this as a favorite
 
Boil or Bleach: Emergency disinfection of drinking water
posted by niicholas at 12:28 PM on December 9, 2022 [1 favorite]


If you’re sure you’ll have access to water and will just need to treat it, I would suggest a Sawyer filter over a life straw. Especially the gravity filter is going to handle a larger amount of water and it’s going to be easier than a life straw to use.

I have a Berkey water filter at home because I had used it in Peace Corps and knew I liked it and I have it for hurricane season as well as bringing to a family beach week where the tap water just tastes a little off to everyone. However, unless you’ll use it day to day I don’t think it’s worth it.
posted by raccoon409 at 12:38 PM on December 9, 2022 [1 favorite]


Best answer: According to their FAQ, the Sawyer filter has the same problem as other filters regarding freezing temperatures. However - the freezing problem only occurs if it's been used once. If it has never been used (and has no water inside that can freeze), there's no risk of freeze damage.

Maybe you can store the smaller filter inside, where it presumably won't be exposed to freezing temperatures? You would need to take precautions in the post-earthquake environment to keep the filter warm though, but you would need to do that anyway for yourself.
posted by meowzilla at 2:56 PM on December 9, 2022


The only filter I'm aware of that is unaffected by freezing is the MSR Guardian.
posted by workerant at 4:58 PM on December 9, 2022


I don't have any specific recommendations, but I like the pump purifiers for on-demand, "need to fill up my canteen" use while backpacking, but the one in my emergency kit at home is a gravity model. Fill it up, hang it, walk away. It's one thing to pump a pint, it's quite another when gallons are needed.
posted by xedrik at 5:10 PM on December 9, 2022 [1 favorite]


I keep my water filters indoors where they won't freeze. But in my go bag I have a Steripen for UV water treatment.
posted by metasarah at 6:21 PM on December 9, 2022


Response by poster: I can't store the filter inside-- that is the problem. It needs to live outside, in the car.

One thing I'm seeing with Steripen is that the battery can fail when it's cold-- even if it turns on the light, it's not strong enough to work. I think Aquatabs and/or bleach are probably the way to go.
posted by blnkfrnk at 6:16 PM on January 5, 2023


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