Originally Posted by ependydad
This almost happened to me in Florida due to a "Y" for my hose failing. Each leg of the "Y" had a shut off and the crappy Harbor Freight shutoff left a trickle of water through. Our "geyser" simply filled the bowl within an inch of the top. Same blast of water through the stinky slinky.
(In my defense- I didn't buy the "Y" at HF because it was cheap, I bought it because it was there and so was I.)
(In my further defense- I now disconnect my blank tank flush hoses after each use.)
I use the same type of Y so that on a long stay I can quickly dump, flush with the black hose and switch back to the white hose. I use a brass blackflow preventer at the Y to back up the one that I assume is built into my flushing system. Just to be safe.
After reading this discussion, I'm going back to hooking the black hose to the camper but not to the faucet until I'm ready to flush.