Rust under Gas Tank

So I noticed after recent rainstorms that water was slowly dripping from under the gas tank area, even the next day, as if it was trapped somewhere. The water drops on the garage floor were clearly mixed with rust, as the drops were orange. The garage floor now has dried rust spots on it. The gas tank has streaks of rust on it, as if this water slowly rolled down the tank. We took to dealer and they say that the exhaust has surface rust, and that the exhaust was built with holes in it to allow residue to escape. But none of this amounts to a warranty claim. I’m skeptical they correctly identified the problem. I think the water is pooling somewhere, long enough to create rust. A picture is below. has anyone dealt with this problem?