Black tank flush valve


Just bought a 2018 pioneer 270 bh, I connected the city water line to the black tank flush valve, but water won’t go to the tank, instead is going to underneath bottom pad that covers the bottom trailer, it got full of water and start dripping from there. I think somehow the house could be loose if something happen, I asked the seller he said he never used it.
I’d anyone had this situation or any ideia what could be?
I have a video but not sure if I can post it here, I didn’t find tool to upload it.


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Staff member
That water at that hose connection eventually goes to your black tank. But before it gets there it runs through an anti siphon valve.
You will need to follow that line to see where it leads. You should find the valve up in a wall somewhere, normally around a bathroom. If your shower has a round access port you might find it there or it could be behind some other removable panel. Check the fittings on the anti siphon valve and observe it while someone turns on the water. It may be cracked.
Leaks from that anti siphon valve are not uncommon.
Some people have bypassed that valve.
If you don't find any problems there you will need to check the PEX line (blue plastic water lines) got any splits. The previous owner may not have blown the line free from water if it was ever winterized.



Thanks Dave, that is very helpful. You right the previous owner probably left that unchecked and during the winter here might have frozen and crack. In spring I will try to trace it and see the issue.
Thanks a lot


Prolifically Gabby Member
With the way the water pooled on the cover under the trailer, it's quite possible the line connecting to the tank fitting itself has broken or become disconnected. If you can remove some to the screws holding the cover to the frame, you may be able to see it.