On our Montana, and most if not all for quite a few years, there is a check valve on the hot water heater where the hot water exits, along with a valve in the convenience center that turns off cold water to the water heater, which effectively bypasses the water heater. The check valve keeps water from coming back into the water heater. The wet area may be from the pressure relief valve above, dripping down to the anode rod, and if not, your anode wasn't tightened enough. The anode has a tapered plumbing thread, so along with Teflon tape or other sealant, the tapered thread seals tighter as it is tightened.
Bob & Becky
2012 Chevy 2500HD D/A CC 4WD