Do you have a portable water filter? Do you keep one in your vehicle, perhaps in a GHB (get-home-bag) or BOB (bug-out-bag) or simply in your 72-hour emergency kit? Do you bring a water filter with you when you hike?
Does the weather freeze where you live? Have you ever wondered if your water filter might be damaged if it gets below freezing?
Maybe you’ve not thought about it before, but you should…
Why? Because freezing temperatures may damage the water filter element –
…and you might not even know it.
That’s right, the internal filter element might crack, and then when you go to use it – the filter will not be properly filtering the water and may allow contaminants to get through.
You need to check with the manufacturers website and FAQ (frequently-asked-questions) to discover whether or not your filter is susceptible to freeze damage.
Generally speaking, if the filter element has been used and therefore is wet, the water inside will freeze at temperatures below 32-degrees-F and will likely crack, damage, or destroy the filter element inside.
As a general rule, if a water filter has been frozen, it develops leaks in the filter element which will cause raw unfiltered water to flow through it without being properly filtered.
Note: A water filter element will remain wet for a very long time, even after draining it or not using it for awhile.
Here’s what they say on the LifeStraw website:
“If your LifeStraw 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.”
Here’s what they say on the Sawyer website:
Before initial wetting
Filter is safe from freezing temperatures if it has never been wetted.
After initial wetting
While there is no definitive way to tell if a filter has been damaged due to freezing, Sawyer recommends replacing your filter if you suspect that it has been frozen.
If you are in freezing temperatures, we recommend that you store your filter in your pocket or close to your person so that your body heat can prevent freezing.
Tips To Protect Water Filter From Freezing
Carry close to your body if it’s that cold…
Keep in your sleeping bag at night.
During the winter, boil the water for drinking instead of filter.
Use chemical water treatment instead of filter when it’s that cold…
How To Know Water Filter Has Been Damaged From Being Frozen
Note: The food coloring method will not work (adding food coloring to water and then filtering). It is a water soluble material, and the coloring molecules are much smaller than viruses – and will likely come through most filters.
One way to suspect if the water filter element is damaged is by its flow rate. A ‘good’ water filter element will pass water at a certain rate (they’re all different). However a cracked or damaged filter element will likely flow much quicker. You may notice if you’re used to the ‘normal’ flow rate.
Another way is to blow air through the ‘clean’ side. If you cannot blow through it, it’s probably not broken. If you can, then it’s probably broken.
When in doubt, throw it out…
Related: Which Water Filter To Buy?