And when they replace it, have them put a) shutoff valves and b) unions on those water lines this time.
Who ever did the install 17 years ago cheaped out just straight-piping it like that. If you ever need to mess with it in the future, shutoff valves and unions make things a lot easier--and only for a few bucks more.
Shut off valve on the hot water TO the house? Doesn't make sense. All you need is a shut off of the cold to the tank. Once that's shut off there's no hot water pressure to the house.
