Our previous RV had the bathroom sink draining into the black tank. One morning, I got up and stepped into water in the floor. DW had gotten up during the night and gotten a drink of water, but failed to turn off the tap. I yelled to her not to flush the toilet, because I knew what would happen if she did. I ran outside and did a quick dump. (We no longer hook up to shore water, and turn off the water pump when not needed.)
Bobbo and Lin
2017 F-150 XLT 4x4 SuperCab w/Max Tow Package 3.5l EcoBoost V6
2017 Airstream Flying Cloud 23FB