Valve leak


New Member
I have a 2012 Keystone Outback, there is a white tube with a turn knob that hangs below the outside floor up front near the tongue. It started to leak water.
I turned the knob, thinking it would release the pressure, to no avail . Im not sure what this valve is used for .
I found some water on the inside floor , right next to the water pump area.
Any advise or suggestions are greatly appreciated.