Black tank flush overfill

[sprintnut]

Hooked city water to black tank flush and got distracted. Toilet was full but not overflowing. Water was running out belly of camper. No water on bathroom floor. Pulled black water drain valve. (It was already flushed out.) Let camper set until water quit running out of underbelly.
Now what? What is broke? How can I check it? Any input welcomed & appreciated.
Russ

[MFL]

I would not say OP was lucky yet? Other than out the toilet, or out the roof vent, there is no place else to go. Something is damaged, likely the black tank. You will need to gain access to see where the problem is, by cutting a window, or removing a portion of the enclosed covering. If you have fiber insulation, that is wet, that will need to be removed/replaced.

Jerry

[QCMan]

Actually, you need to fix how you flush the black tank. Things can go very wrong when attention to detail is lost. When flushing, if anything distracts you, turn off the flush line. You got lucky once. The next time could get very ugly.

[Memphisdoug]

My guess is that you have a loose fitting vent pipe coming out of the top of your black tank and that is where the water that was in your underbelly was coming from. If that is the case there probably isn't anything you really need to "fix"