Does Freezing Destroy Water Filters?

Does Freezing Destroy Water Filters? I remember hearing a few years ago about somebody who got sick after using a water filter that had frozen, and I basically thought that it made sense that filters might well break if they froze.

After all, water expands, and we’ve all seen things destroyed by water expansion. In some cases, we’ve seen it all too dramatically. 

Following the actual important prepping information, I’ll share the story about how I learned the hard way about exploding liquids.*

Not really wanting to risk one of my own filters, I looked it up

There’s surprisingly little information by the manufacturers about the effects of freezing and how it affects their filters. 

When notice a fact like this, I always wonder “OK, why don’t they talk about that much?”

On the one hand, they sell their filters as these rugged survival tools that will get you through just about any survival situation.

On the other hand, they don’t want people who use their filters to get sick, so they should be very upright and forthcoming about this particular issue.

Even though we are getting anatomically unlikely now, on the third hand, if people destroy their filters by letting them get frozen, that’s an opportunity for the company to sell even more filters.

I don’t know if it is all of these factors, or none of these factors, or a combination of some, but there’s very little information out there about freezing. (Spice’s note: I couldn’t find anything on my in-bottle hiking filter until I actually opened the package and read the fine print on the insert. It’s upshot: Wet filters are ruined when they freeze; really dry filters should be fine.)

Let’s take a look at what I did find from several popular manufacturers, taken directly from their company documentation.

Berkey Filters

Berkey Filters comes out strongly stating that customers should avoid putting their filters in “sub-freezing” conditions, even if they have never been wet.

As a part of their “FAQ: Frequently Asked Questions” they state:

Why do your instructions say : “Do not allow filter to freeze?”

“We strongly advise against freezing your elements as a general rule of caution. We also advise against storing the elements (even unused) in sub-freezing climates. The concern with freezing the elements is that any cold or freezing water will expand inside in the element, thereby increasing the pore size and ruining the element.

Whether the elements are unused or used and fully dried out, a small amount of moisture could still exist inside the element, especially in predominately humid climates. This moisture could expand inside the element and render them unusable. Please note that this recommendation applies to ALL our Berkey® elements, including the Sport Berkey® water filter bottle element. Freezing your element and rendering it unusable will also void your warranty coverage.”

Lifestraw filters

Lifestraw formerly had information about freezing on their website, but has since removed it for some reason. Fortunately, we can look at a cached version of their website, recorded when the site still had the information on freezing.

Cached version of a page from the Lifestraw Website states: 

“If your LifeStraw Family has been used, and is then exposed to freezing temperatures, water inside can freeze and crack the filter. You may not see these cracks, so we recommend never letting it freeze once it’s been used. When camping at high elevations or freezing temperatures, be extra careful not to let it freeze.”

Sawyer filters

Sawyer takes a slightly different approach, one that’s actually a bit annoying, because they don’t really answer the question definitively as to whether freezing damages the filters.

In their FAQ on their website, they state: 

“While we have no proof that freezing will harm the filter, we do not have enough proof to say it will not harm the filter, therefore we must say that if you suspect the filter has been frozen, to replace it — this is especially true with a hard freeze.”

Katadyn filters

Unfortunately, Katadyn filters (despite being some of the best known and most expensive filters around) don’t appear to have sold documentation available about freezing damage other than one vague reference to “cracks” that I found.

I checked their website, did a full search, and even opened up some of the more popular filter’s manuals (like the manual for the handy for those living near salt water prepping filter Survivor 35 desalinator and the Katadyn Pocket Filter (the one Katadyn we own)) and found the following rather unhelpful statement:

“Inspect the ceramic for cracks after cleaning, if you dropped the filter or if you had freezing temperatures. If the filter shows cracks it will no longer protect you from microorganisms.”

Even more strange, Katadyn is a Swiss company, and last I knew it gets really, really cold in the winter in Switzerland.

The Bottom Line

It’s pretty obvious that just about any brand of filter can be damaged by letting them freeze, especially if they are previously used. 

Here in Salty and Spice land, we keep any used filters indoors during the winter unless we are actually out hiking. Even then, we keep them close to our body so that our body heat will keep the elements from freezing.

We recommend you take a look at the manufacturers recommendations for your filters, and follow their guidelines.

I hope this helps.

*How Salty Discovered The Explosive Power Of Frozen Liquid

The following is entirely optional, but it’s kind of a fun story if you have a couple minutes to read it.

I learned about the explosive expansion properties of liquid when I was about 10, living in Okinawa (I’m a military brat). Back in the 70’s, pop came in 12-ounce returnable bottles, and we generally had a case of cola in the pantry.

This was during a drought, so there was no running water on the island (we lived for nearly a year with no running water) so it was pop or milk for us kids (there wasn’t bottled water available, either, and no water to make tea or to mix juice concentrate into).

As usual, my middle sister (the one I never could get along with as a child) had taken the last cold one when she got home an hour before me and hadn’t put one in to cool down for me. Typical. I was thirsty, and the pop was warm, so I broke a firm house rule and put a bottle in the freezer. At this point in time, I think it’s pretty obvious this story is not going to end well. 

The Dirty Deed

Of course, right after this happened my friend Danny came over with some really important kid business or other, so I grabbed a swig of milk out of the bottle (yet another house rule bit the dust on that one) and out I went, forgetting completely about the pop in the freezer.

Well, the pop POPPED, and made a total mess of the freezer. My mother was livid, as one would expect, and she had just lined the three of us up for the inquisition, oldest (Mammy, who occasionally writes for us here at 3BY) to youngest (me) when my father walked through the door.

Mom was a tough disciplinarian who one didn’t dare cross. Dad? He was scary. Unfortunately, dad heard what had happened and “stepped in to take care of the matter”.

Dad

He looked us strait in the eye and said “I’m only asking once. Who did it?” 

This was not 10-year-old Salty’s finest hour. I slowly, like the sneaky little rodent that I had turned into at that moment, pointed my finger towards both of my sisters.

My oldest sister, knowing that she was entirely innocent of the crime, pointed towards the two of us. In effect, this left both kids on each end pointing towards the middle sister.

She was my father’s favorite, and her cries of outrage and innocence were quite convincing, so she ended up not getting spanked… she was, however, grounded and not allowed to play any of her Beatles albums for two weeks. I suspect this last part was more because my father HATED the Beatles and this was his way of having two weeks of peace and quiet.

Yes, I was a slimeball

I admit it, that really wasn’t my finest moment on the Earth.

Did I feel guilty? Of course I did… but I’ve got to be honest, the amount of guilt I felt was mitigated by several factors.

1. She had it coming. A few days ago I told a story about my middle sister knocking me out cold with a Whiffle Ball Bat, then laughing about it? Well, at the time of the “Pop Popping”, I still had a rather large knot on the back of my head from that experience.
2. She was constantly breaking the same rule, and putting pops in the freezer to cool them down. Of course, she did this generally after her bratty little brother had taken the last cold one when he got home from school before her, and hadn’t put more cold ones in like he was supposed to.

I know, the one question you all want answered… did I ever fess up and admit it?

Yes, but not during my father’s lifetime. I did own up to it when my sisters and mom and I were having a holiday get-together about 10 years ago. 

My middle sister was going on-and-on about how unfairly she was treated during the “Pop Popping” incident, and my oldest sister said “well, you know it wasn’t me. I was still at school at marching band practice.”

Time seemed to slow as her gaze of death turned upon me

Those beady little eyes of the middle sister turned on me and locked in like a cobra who had it’s prey dead to rights. “It was you…” she hissed, the venom flowing through the air between us like waves of future pain… “It was you…. admit it….!”

Caught in the eyes of the ultimate predator, a sister full of moral authority over me, I stammered. “Well, yeah, of course it was, who else could it be?”

She grabbed the nearest heavy object (a paperback copy of Hawaii by James Michener sitting on mom’s chair arm) and with a fastball that would have made Nolan Ryan proud she hurled it right at my noggin.

I saw it coming and ducked, and I almost got out of the way… the spine of the book cracked me right on the same exact spot that unprovoked Whiffle Ball Ball had hit me 40 years before.

Ask me if I felt guilty after that. No, I don’t think you need to ask. You know I didn’t.