This can be found in any part of the RV, but is particularly prevalent in corners, under mattresses, and in other small nooks and crannies. Mildew thrives in a damp environment. 1. A strong musty, earthy odor… Being a health and safety practitioner, I know what causes that type of odor. If you have a musty smell in your kitchen, there’s a good chance that you have a leak somewhere. Had damaged laminate flr beneath from dripping consistently over time. The sink and sink drain actually smell fine - it's the cabinet underneath it. The trap is so-called because it "traps" a little water in the part shaped like a "u". //