[DutchmenSport]

The first thing I'd attempt to do is use a stiff toilet brush and brush all around the hole in the toilet where the slide valve slides. Sometimes, small pieces of crud get's caught on the rubber seal preventing the slide blade from closing completely. Normally, this allows water to drain on down into the tank, and also allowing black tank oders to come up.

But in your case, it's possible some crud on the rubber slide seal could prevent the slide itself from closing completely, allowing for a very slight drip, but the seal in the bottom is sealed, thus causing a risk the bowl could potentially fill up with water and overflow.

This is another reason why I never hook up directly to shore water and run everything from a garden hose. I always fill my fresh water tank and use my on-board water pump. Whenever water run anywhere, the water pump will kick on. Even very slight leaks, or a faucet not turned off completely, or the toilet slide not closing completely will kick on the water pump and then we can hear it run. When it does, we know water is going somewhere and I always check things out. Other than the ice maker kicking on, we've caught water drips at all the faucets and toilet many many times this way, when they just did not get turned off tight.

I've also measured how much water it takes to kick on the on-board water pump. It takes less than 2 ounces of water running for the water pump to kick on. With no pressure tank installed, that's not much water. So, if a drip occurs, and you hear the pump kick on when it shouldn't, at most, it's only leaked less than 2 ounces of water, not enough to hurt anything, and yet, the sound of the pump let's you know something is not right...giving you time to check it out.