Rusty water pipe

We purchased our 5w this past December, and recently when we went to pull the lever to empty the black tank, the lever fell off! While underneath the rig to determine how to fix it, (new bolts, etc.) my husband discovered the water pipe is covered with a fairly thick coat of rust. Any suggestions how to fix this pipe? Obviously the dealership didn't even look under there, or if they did, said nothing about it.