I d replace the water heater.
Atwood water heater tank cracked.
These minerals calcify and form deposits inside your water heater which eventually causes enough stress to crack it.
Most water heaters rely on a simple set of heating elements piping and controls in order to operate.
One of the primary issues with older water heaters is the buildup of sediment caused by natural minerals in the water.
The tanks are so thin that welding a crack isn t likely to succeed.
If you have an atwood and it is functional other than the leak get it repaired.
Trailer life and motorhome magazines bob livingston and bill gehr show you how to replace the inner tank of a leaky atwood rv water heater.
I called a couple welding shops and was quoted 20 to patch the screw hole a crack might be 40.
When i first put a hole in mine i looked for a replacement and was floored at the cost.
The pic in your signature suggests that there are more than 2 of you so i d upgrade to a 10 gallon if there was room for it to fit.