Hey, kman. Welcome to MD.
1. The best local shop is Maryland Homebrew in Columbia. www.mdhb.com
. They are awesome.
2. Not sure of the water in Bethesda, but I brew with Baltimore tap water straight from the faucet. I dont notice a Chorline smell with my water though.
3. I bottle so I dont know everywhere that will fill a tank, but I am pretty sure that the MDHB store will.