Neighbors sink was clogged today. Tried plunging it, nope. Tried sticking one of those plastic barbed drain unclogging sticks in it, nope. Finally got out a spiral drain snake, stuck it in sink, worked at it...low and behold a minute later all the water in the sink went rushing down the drain. So far so good!
I even let the faucet run to flush the drain out as I was taking the snake out....but it got caught on something and wouldn’t come all the way back out.
....then I noticed all the water on the floor coming out of the cabinet under the sink. I’d put the snake right through the thin walled trap elbow and made a hole in the pipe.
Drain was still clogged, all the sink and faucet water was just running out the hole into the cabinet below.