The black gunk in my pipes

[BobT]

I live in the bottom floor of an apartment building and every few years or so, the plumbing backs up and my bathtub regurgitates water and some foul smelling black gunk.

So, what is the usual composition of this gunk that I had to mop up from my tub? Is it stuff like hair, skin, and soap or is there any other sort of nasty organic stuff that I need to worry about.

Fortunately, this only happens once every five years or so.

[Shiva]

There's a technical term for that stuff.

Sewage :eek:

[BobT]

It wasn't quite as smelly as sewage, however. It had an odor, but not an overwhelming one.

The sewer line didn't back up. It's just that nothing could get to the sewer line. So it ended up in my bathtub.

[Shiva]

Lemme get this straight.

This stuff comes up out of the drain, right?

[BobT]

To be precise, there was clear water bubbling out of the drain. Then I took my plunger and tried to free up the clog. All that succeeded in doing was bringing up all this black gunk.

So, what I think was happening was that my neighbors' water ended up in my bathtub and then I pulled up the stuff that was stuck in the pipes, although not all of it as it took a plumber to remove the main clog.

So, what is the stuff that is presumably stuck in my drain?

[handy]

Pipe gunk. Could contain sewage too as the toilet drain is the same as the bathtub one.