[outwest]

Some trailers have heater bypass valve in the exterior convenience center. Our Vantage has 3 valves there: hot water heater bypass, winterize mode on/off, fresh water tank fill on/off

If you don't have bypass valve in exterior convenience center, you'll have to try to find where they hid it. You should be able to get to the interior side of the water heater by removing a panel that's screwed in place (or could be as simple as opening a cabinet door, depending on trailer. On an old trailer we had it was under a bed, on another it was under kitchen counter in cabinet, in current trailer it's in hallway behind slatted panel) Once you have access to the water heater from inside the trailer, if the valve(s) isn't/aren't visible there I would look near the water pump.

To find the water pump I would suggest turning water pump on, listening for the sound of it running, and use that noise as a guide. It could be under a trash can drawer, behind a panel that's screwed in place, under a bed, etc.