Black Tank valve failure scenarios

Mine sprung a leak last season. The 30-year-old O-ring had finally had enough. It was a pretty significant leak that I had to hold back with the cap. Ultimately I had to release the flow by removing the cap in order to make a repair. It was not pretty, but I was prepared with gloves and kept as much distance as possible when I removed the cap. I hosed everything down into the dump station and did a complete dump and rinse. Replacing the valve wasn't hard or particularly unpleasant - it's kind of what you sign up for when you get an older RV.

My gray water valve failed when the handle pulled out of the gate, leaving the blade closed behind a full tank. Had that happened to the black tank I'd have a whole different story to tell.