Subject: 9. Can I use chlorinated water with my starter?
No. If you have chlorinated water, dechlorinate it first. The quick way is with a carbon filter. You can also boil it or just let it sit out uncovered 24 hrs, provided that your water treatment plant chlorinates with free chlorine (as ~85% do), and not with the stable form of chlorine, chloroamine. This cannot be boiled or evaporated out.
Dechlorinated water is not just some yogurt and granola health food nut idea, it is very important for the health of your culture and the success of your sourdough baking. A microbiologist friend of mine confirmed this observation with laboratory techniques.
Sourdough QA|Sourdough FAQs|Darrell Greenwood's Home Page
Links changed to carlsfriends.net 10/8/16