Originally Posted by BILLYBOBTX
Nope. Something is different. After getting Craig's response I went and looked at the bowl again and it was bone dry. There is almost always a quarter inch of water in there. So something is not lining up properly.
The RV toilet seal (that keeps water in the bowl) is a common maintenance item and I suspect they all will give out (leak) with time, even more often than the water intake valve in my experience. Some RV'rs use a little mineral oil once in a while in the bowl (with no water) to help lubricate the seal and the slide, however that hasn't really provided me with a lot of long term satisfaction other than that it does help if the dump slide part is sticking and if it is sticking enough and not fully closing, that could keep the water valve open a little bit and could be the cause of the water to continuously fill the bowl as you described. I would try a bit of mineral oil though, as it is easy to do, just pour in a little, work the valve, then let a couple of inches of oil stay there for a few hours or overnight.
Keep in mind that these are two different components (seal and intake valve), however if it was mine I would replace both the seal and the valve at the same time if both are having issues. If you know that the water filling the bowl only occurs when the slide dump valve isn't closed or closing all of the way, then perhaps just changing the seal is all that is needed.
Here is a video if you choose to do the work yourself. It is not too hard to do, but if you call an RV tech, you may as well have him do both (water intake valve and dump slide valve seal) as the service call itself will justify not having to call an RV tech out twice.