The homes in TV - at least the more recently built ones - have a catch pan installed that the hot water heater sits in. The drain line for the pan is plumbed to exit outside of the house. Thus if the water heater starts leaking, the flow is contained.
Our place in OH has a catch pan installed as well, even though the water heater's installed in the utility area of the basement. It would still keep the basement from getting flooded in the event of the hot water heater leaking. The drain is routed to a floor drain that empties into the sump pump pit.
Bill
