system
Given the following post, respond as if you're commenting on Reddit:
human
What exactly does a Britta water filter do to my water?
gpt
A Britta filter contains Ion-exchange beads and activated charcoal. Ion-exchange beads essentially switch out any heavy metals (copper, lead,...) with sodium or potassium. *They also swap out chlorine with sodium to take away that "chlorine" taste tap water usually gives.*(Not sure about this part, but the other parts are spot on).
Activated charcoal is basically manufactured carbon that has little "pores" that catch impurities in the water.

So basically your Britta filter is going through chemical reactions using the beads to *swap out sodium from the resin on the beads with the calcium, chlorine, ect... *(again not sure about this). Leaving the elements you don't want in the water stuck on the beads. It is also being ran through little carbon pores which should catch the bigger molecular impurities.