How to rid the musty smell from water leaks in RV?

Many RV's don't have padding under the carpet which is just stapled to the wood floor. Not sure why your carpet got wet but many would shampoo the carpet and then use combo of heat/fans to dry out the area ... if it still smells then look for wet insulation or some other issue. Normally with smells I would recommend coffee grounds etc but when smells come from dampness then you should be concerned with mold which can be harmful.