OK so usually the waste tank valves can be sticky or binding a bit and sometimes don’t close all the way, all this is fairly normal within reason, and often times these valves will get either easier to use over time as things wear in or harder to use because of things wearing out or binding. What you don’t expect is that with your new RV that you would have clogging issue and valves that simply refuse to close all the way. That is what happened to one of my clients recently.
First off the tank wouldn’t drain even though he had the valve all the way open, I went and investigated only to discover that a major blockage was occurring at the valve, I recommended using Draino and a large quantity of it to clear the blockage. I wouldn’t normally recommend the use of Draino as it isn’t good for septic systems.
After several hours the blockage cleared and the owner was able to start using the black tank again. With one exception that the valve wouldn’t close fully now, they worked with it like that for a couple days until i could get back to help out again. Upon investigation and some pretty smelly work, I opened the belly of the RV and then removed the black tank valve, much to my surprise I saw this Silver object that was sticking into the valve opening. I grabbed it with a pliers and then discover a 6″ crescent wrench that was obviously dropped into the black tank at the factory.
The wrench and valve shown in the picture is what I removed and the shows the damage it did to the black tank valve. Needless to say, things are operating a lot more normally now!