Joseph wrote:

I have a bathroom that has two sinks. The drain on both of them is
slow. I have tried all the various drano types with little or no
improvements. I tried using a water balloon thingy that attaches to a
hose and inserted it deep into the vent pipe from the roof until it
reached the floor. I was thinking that the water pressure will blow
out the obstruction and to my surprise the water overflowed from
another vent pipe inside the attic that I did not know existed because
it is burried under the AC/furnace train. Needless to say that
backfired. Now I am at loss of how to proceed. I know I have an
obstruction (probably hair) that is far down the drain. I would like
to use a snake but I am afraid that I could not tell where the snake
will end up because of the maze of drain pipes and vent pipes behind
the wall. Any ideas?

Thanks,
Joseph

Yep, time for the snake. You can rent a small hand-held powered
unit made just for this size job.
The big trick is to make the snake go *down* the drain at the
San TEE, rather than *up* the vent.
Better snake cables with optional cutters can use a "downhead"
cutter which makes it easier.

If you can see the San TEE in the wall, you could guide a
cheapo snake-in-a-drum down the drain. These are available
hand-powered or to fit a drill motor.

Jim