Hi, my bathroom lavatory is overflowing and the water is not on. I drained the lavatory, removed and cleaned the trap and drain line until it disappears into the wall. But there is a slight, steady flow of water coming back out of the pipe that disappears into the wall. Can you help?

Hi, my bathroom lavatory is overflowing and the water is not on. I drained the lavatory, removed and cleaned the trap and drain line until it dissapears into the wall. But there is a slight, steady flow of water coming back out of the pipe that disappears into the wall. Can you help?
Yes. You have a blockage in the horizontal line inside the wall that will have to be snaked out. Remove the "J" bemd from the trap and take your hand held snake,( if you don't have one then purchase one from your local hardware store) and run it up into the wall, (see image).
You'll hit a bend about 8 inches in. Work your way around that and you only have 5 more feet to go. Reassemble and test with a sink full of hot water. Good luck, Tom