What's the code on water heater replacement, concerning the metal tray under the heater?
My heater is installed in an attached storage room, on a concrete floor that slopes away from the house. Does Code require a tray?

Some local codes require a "heater pan" installed and piped to the outside. In my area you would be OK but call the Building Department and see. Seems tome If you have one that's been in for a while it should be grandfathered in.
Good luck, Tom