Leaking black tank flush hose

One day while camping I started to notice water dripping from my lowpoint drains. On the previous day I had seen water pooling under one of our dinette benches which I attributed to condensation during the very rainy day before. I tightened the low point drains, which really didn't need tightening ,, and thought everything was OK until the next trip when both happened again. Both times I had my freshwater system pressurized but the leaks only seemed to happen rarely but when they did the water was noticeable. I found that the water dripping at the low point drains wasn't coming from the drains themselves but was dripping from the subfloor through the access holes and down the short length of hose at the drain. 'Great' I thought, a hidden leak under the floor. Brother.

I traced everything I could but didn't find anything obvious and so at the end of the trip I emptied my black tank and flushed it to go home and made plans to take it for professional help. Hallelujah and eureka! It began leaking actively in the same spots and slowed then stopped when I stopped flushing. I realized that the previous leaks were noticed on days that I had flushed the tank.

Warranty work at the dealer found a screw driven through the black tank flush hose where it travels under the toilet to the top of the black water tank, presumably during the manufacturing process. Not sure how the technician accessed it but I imagine he used a lift and had to partially release the tank itself to get to the hose section. Work was covered by warranty but of course the bother and the 110 mile round trip at 12 mpg wasn't.

Hope this helps anyone who encounters this mysterious leak.