Why shouldn't Berkey® water filters be allowed to freeze?

It is not recommended to let your filters freeze. Similarly, it is not recommended to store the elements (even unused ones) in very cold climates. Indeed, the residual water contained inside the element will expand and consequently increase the size of the pores and eventually destroy the element. Whether your filters are unused or even used and completely dry, a small amount of moisture may remain inside, especially in predominantly humid climates. This moisture could expand inside the filter and render it unusable. Please note that this recommendation applies to ALL Berkey® items, including the Berkey® Sport Bottle. Freezing your item and rendering it unusable will also void your warranty coverage.