27/07/2026
Your water filter probably isn't broken — but it might not be doing what you think
There's a chat doing the rounds on forums that squeeze and straw filters are basically useless because people have gotten sick using them. Worth untangling, because a "filter" and a "purifier" are different things, not two names for the same product. A standard hollow-fibre filter reliably strips out bacteria and protozoa, but its pores are too large to catch a virus — that's not a manufacturing flaw, it's just what the product is rated to do.
Since these reports are written for American or European trails: Australia's own bushwalking safety guidance and national drinking water research point to protozoa — Giardia and Cryptosporidium — as the dominant documented risk in our wilderness water, not viruses. Viruses still need water boiling, chemical treatment or UV purification.
So if you are looking for a device to do both - some products combine a fine membrane with a built-in chemical or electrostatic element specifically to also catch viruses. Its important to be aware of the difference and always read the fine print :-)