I used a device sold to keep the Fridge/Freezer doors open.. But now full time
Atwood. Most water heaters have a plastic plug, not anode Aluminum tank.
I replaced mine with a LARGE brass valve, well taped to prevent electrical contact, I do not need to remove it, just open it
Campign world sells two versions of this, one uses a standard radiator drain valve,,, I tried that.. Then I did it right with the other one
Big brass "tube" outlet, steel pin.. I slip a 1/2 inch PVC with notched ends over the pins Twist to lock (the notches are "L" shaped) and open the valve, water is thus piped clear of the RV.. Turn the other way to close the valve, and unlock the pipe from the pins and store in teh bottom of the WH compartment.