[HayZee518]

Look under illustrations by "lazypup." He has some good diagrams that explains the waste lines in a house. If your main vent is blocked by a bird's nest or there is a blockage inside at any bend downstream of the clog, the effluent will not flow. Under the sink is a P trap or an S trap. This trap must allow water to flow - don't use chemical cleaners if you can help it. When you take the trap apart you'll get this crap on yourself and it burns! I'm assuming you have a two tub sink. One side has the disposal the other is just a tub. The disposal and the tub join at a T and then goes to the main drain and trap. If your system isn't glued up then you'll have "slip joint" fittings. There's a metal or plastic nut with a tapered plastic or rubber o ring between the two pipes.