Buildup in trap and drain pipe - black sludge

[Hightechburrito]

As part of my continuing bathroom renovation, I've moved onto replacing a sink and vanity. When I pulled the old trap assembly out of the drain stubout, it was about half blocked with black sludge. I can tell it has hair in it and seems a bit sandy/gritty. The pictures show after I pulled as much out with my finger as possible. I didn't remove anything from the waste arm since I'm not planning on reusing it.

It didn't seem like the drain was running slowly before I pulled everything, but I don't use this sink much so I can't be sure. The sink I do use is right behind this one and drains fine, I can run the sink full blast and there's no backup at all, so it seems the drain is fine past the stubout for this sink.

Should I do anything here before the new vanity goes in? What's left in there is solidified a bit, can't really dislodge any more with my finger. I'm a little concerned that if I go at it with a tool it will break off and go further down the drain and clog everything up. I'm not certain, but I believe this drain goes down a vertical drain pipe that is shared with the sink on the other side, then into the main waste line shared with the toilets and shower/tub in these bathrooms.

Access wont' be terrible once the new vanity goes in, so would it be stupid to install the new vanity and see how it drains? Then use some enzyme based drain cleaner over the next few weeks and check it again?

Reading some other threads, I see comments about using Bio Clean to help with buildup. But will it help with somewhat solidified buildup? I don't think 'Bio Clean' is available in my local stores, is it basically the same as other enzyme based cleaners? I think I can get it online (2 lbs for $50, how long would that last me?), and it would probably show up before I have the vanity installed.

I've also seen in some other threads comments about liquid soaps not being helpful with drain buildup. This is the bathroom my kids use, and they can go overboard with how much soap they use. Could that be related at all?

Thanks.

 

[Helper Dave]

It's VERY common for bathroom, and kitchen drains to be partially full of the black sludge. Greasy, oily, fatty stuff sticks, catches solids, and etc. It builds from there. It may not affect how a pipe drains for a long time, though.

I would recommend exactly what you had planned. Just put the new stuff in, and use an enzymatic drain cleaner. Bio Clean, Green Gobbler ... there are a few others that work.

Clearly, things on the same line are fine, so I wouldn't worry about it. It's when multiple fixtures back up, or when a fixture causes backup into another fixture that you've got a real problem.

 

[Sponsor]

 

[Reach4]

I would rod the drain to where the pipe diameter increases, while you have easy access. Where lines turn from vertical to horizontal is a common place for a clog.

 

[Hightechburrito]

Thanks.

I have one of these: https://www.lowes.com/pd/General-Wire-1-4-in-x-25-ft-Galvanized-Wire-Drain-Auger/1002472234. But it just passes right through the hole in the buildup. Should try spinning with the tip against the buildup and see if it breaks it up? Or do I need something with a larger diameter tip? Or another tool entirely?

 

[Hightechburrito]

I went at it with the auger I had and was able to open the hole up to about twice the size, pulled out a few big chunks of gunk along the way. What's left seems pretty hard. Going to try some enzyme based drain cleaner for a few weeks then revisit.

Thanks.

 

[Reach4]

How big would you estimate the passage is now? Is it a straight shot where you could push on the buildup with a pipe?

 

[Hightechburrito]

How big would you estimate the passage is now? Is it a straight shot where you could push on the buildup with a pipe?

I would say it's about a 1" opening, before it was probably half that.

My other sink is right behind this, and I can see the waste arm past the opening. I suppose I could push on through the stubout in that bathroom. I'd hesitate to push on it from this side in case it falls down the vertical drain and clogs that.

 

[Reach4]

You could bring in a drain cleaning specialist with the big machine and cutters. Get your other pipes cleaned while you are at it. There may be other accumulated crud over the last 40 years.

You could rent the big machine, but that takes practice to do the job without getting injured.