Gas Water Heater

I live in California and our water heater is outside against the back of the house. We need to move. We only 5 feet from the fence on the north side of the house, so I suppose there's not enough clearance. The other option is close (maybe a foot or two) of the electrical box on the south side. I was wondering if there are restrictions in this code.

It is absolutely not the case inside to move it, and the garage is detached. No tank is not an option at this point.

Maybe a gas heating near the fuse box?

You can not put anything within 3 feet of an electrical panel.