Is my plan for fixing my water heater leak bad?
If the water on the floor is from the water heater I would fix that problem before I do anything else. If it is coming from the tank then it probably needs replaced. You can raise the tank as high as you want but if you do I would also replace the copper flex water lines and the flexible gas line. Once those lines get older, the flex gets hard and rigid and may break when you re-bend them to the new height. A broken water line or gas leak could be a disaster. And, by the way, the piping off that T&amp;P relief valve is soldered and is not welded indicating to me that you should seek help from someone more knowledgeable than yourself in what you want to accomplish.