Originally Posted by Teamaron
Does it matter if hot is run through it? I mean you only heat water just before a shower or when you need it.
All other times doesn't the water just flow through the tank when it's off?
I know if I use faucet water and turn it to either side it stays cold when hot water is off and pressure remains the same.
When the camping trip is over and it's time to dump the black and gray tanks, I've still got hot water left after washing my breakfast dishes. So, I use that hot water to flush the black tank, courtesy of my modified external shower hose. Helps keep the tank cleaner and less odorous in between trips.
But if you routinely shut off the water heater until right before you take a shower or wash dishes to save on propane, then you probably don't have leftover hot water when you flush your black tank, and it won't matter to you.