Could someone tell me where in the Bible it says the flood waters came from some source other than rain.
There is some mention of a concept called "The fountains of the deep" in one of the two expositions of the flood story. Physical evidence that this concept ever existed (and you'd expect there to be some physical evidence of the source of a billion cubic miles of water, unless perhaps God erased the evidence in some kind of guilt-trip); zero, zilch, nada, zip.
Where the fountains of the deep are mentioned...Gen 7:12
Gen 8:2 refers to it also.