Tap water for casein bichromate?

I've been reading through one of Christina Z Anderson's books, and she mentions that tap water works fine for the pre-shrink on bichromate prints. I've been using distilled water for the pre-shrink, gelatin sizing, and hardening with formalin (Anderson uses PVA sizing). I switch to tap water when I start exposing and processing each layer, and that's worked great.

Has anyone tried using tap water for sizing and hardening? I'm doing very large prints, and switching to tap water would be much easier (not to mention cheaper). I worry that the minerals and/or chlorine in the water might adversely react with the gelatin or formalin. I suppose the only sure way to tell is to try it, but I'm curious if anyone else has any experience.

Thanks!
Josh