My 40 gallon gas water heater is leaking from a drain tube which goes to the out onto the patio side of the garage. The house has been empty since May 1. A new tenant moved in a week ago. The wife says that when she turns on the shower, the water starts rusty and then clears up. Do I need to replace the water heater?
I bought the house 6 years ago with the water heater already installed.
How do I find out how old it is? The serial number is #129 410 3593.
It has 34,000 BTUs.

Help!