[JRTJH]

Most of the "odor" from a water heater comes from stagnant water being "decomposed" and reacting with the magnesium anode rod. There are several things that will help reduce that odor. First, drain/flush the water heater, add 1 cup of Clorox to the tank, reinsert the anode and fill the tank. Let it sit overnight, drain/flush and reinstall a "cleaned" or new anode. If the problem recurs, either drain the tank between "extended use" and/or install an aluminum anode rod. The factory "magnesium rod" does react with some local water types to create a sulphur compound in the tank. Some types of water are more prone to that with a magnesium anode, some with an aluminum anode.

If you're going to store your trailer for over 2 or 3 weeks and experience "smelly water", you may benefit from draining your water heater before putting it in storage.