Q:

What's involved in moving a hot water tank to the garage

After a recent electric hot water tank leak on the second floor - I've decided to relocate the tank to the garage. 
On the other side of the block wall in the garage - I have the laundry room - so we can tap into the h/c lines. 
The electrical panel is inside the house right near the entrance from the garage. 
Lots of questions...
What should I be aware of while doing this - is this even a good idea? 
Should I keep the tank on the concrete floor or should I use some kind of barrier (over even a drain pan)
Should I use expansion tank? 
Can I just connect to the h/c water line currently feeding the laundry room? 
Appreciate your feedback and guidance/suggestions. 
Thanks

A:

Have you considered adding a drain and rigid metal drain pan to the water heater in its current location.  That's likely to be a much saner approach? 
To move an electric water heater, the new location needs the following:

220v outlet on its own circuit with heavy-gauge wiring rated for an electric water heater.  This is doable.  If there isn't already such a circuit, you can hire an electrician to put in a new one, and you said the panel is pretty close by. 
An incoming cold water line, which will be harder, but if worse comes to worst, you can run a PEX line from the incoming cold water line on the second floor to the new location in the garage. 
An outgoing hot water line that serves as a trunk feeding the rest of the house with branch lines going to the fixtures.  This is going to be the deal-breaker.  The previous location probably has the correct trunkline hot water plumbing.  If you seal that off and make a new input in your garage, you'll be supplying hot water to your whole house through a former branch line, which is narrow.  Hot water pressure may decrease, and the time it takes to get hot water to distance fixtures will rise quite a lot.  And you may be able to run fewer hot water outputs at once.