Question:
A thought occurred to me, perhaps a bad thought. But that's what I'm here to find out.

Has anyone tried a Brita water filter for backpacking? At $5 per filter it would be a steal.

Of course it has no pump and you'd have to wait for it to drip. Perhaps a pump could be improvised. But let's leave that matter out of this.

I'm sure it would clog faster than a filter meant for backpacking. So take two.

The bottom line is probably the particle size that it filters. Does anyone know what this is?

Answer: You will see nothing in the Brita literature about removing bacteria, Giardia, cryptosporidium, or viruses.

To quote from www.brita.com: "The BRITA Water Filter Systems are not intended to purify water. Do not use with water that is microbiologically unsafe or of unknown quality without adequate disinfection before or after the system. Individuals requiring water of special microbiological purity should follow the advice of their doctor or local health officials regarding the use and consumption of their tap water and BRITA water. The BRITA Filters have been tested and verified to remove only trace amounts of fluoride over the life of the filter. "

Different filters will filter different things.