I've read all the threads on these boards and also researched other resources. Our local tap water, from Hetch-Hetchy, is treated with chloramine, according to San Francisco PUC. But the local LHBS says a) Campden tablets will not remove chloramine from water and b) most local brewers don't bother treating their water except to add small amounts of gypsum.
Nice store, nice people, but are they in groupthink on a)? Hard to measure b.