My kitchen sink fills with dirty water

[andrewc427]

Hi I own a 2016 big horn 3760EL and have recently started having water flow back up into kitchen sink when we use washer. And it’ll drain in a day or two. Also the washer will fill up with waste water after it drains. Kitchen sink as well. Can’t even wash dishes for 5 minutes or it’ll fill up. I’ve poured liquid heat and other products and they seem to come back up the sink and washer. I have 3 tank valves cut into underbelly and manually opened the first grey tank valve and it opens good well both do. Black tank valve I can’t pull from handle it feels completely stuck. Any suggestions ?

 

[hoefler]

I would get all 3 valves open first of all. Then verify wich one goes to which tank.

 

[rhodies1]

As howler stated get them open. It sounds like your valve maybe only partially open or not at all. Your tank is full and flowing back to the area of least resistance. I would not put anymore water down the drains because the pressure could split the tank,force the connection in the tank to fail or even pop a gasket out of the valve. Realistically this should be a grey tank issue and nothing to due with the black tank