We had enough of dealing with that. So far, they hadn't burst, but we didn't want to take the chance that they would at some point. Today, a plumber came out and ran new lines, away from the back wall, of PEX (cross-linked polyethylene) tubing. He also removed the gas line to the garage, since we are not going to replace the heater out there (it's got a cracked heat exchanger). While he was here, he also fixed what we thought was a bad faucet in the shower. Whee.
This winter, we won't have to worry about any pipes freezing. It's going to be nice.