RV water pumps are normally loud and do vibrate a lot when running. There probably isn't anything wrong with it or the way that it is mounted. In my old TT it was mounted under a bed and the mattress and bedding did little to quiet it down. In my new TT it is under the vanity in the bathroom and it too is loud and vibrates like the old one did.
2014 V Cross VIBE 822VRBS
2017 Silverado 1500 crew cab 4x4