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Re: Odd black mold like substance in sink drain

My master bath sink accumulates this as well, to the point of clogging about every 9 months. I haven't tried bleach, though I probably will to see if this keeps it under mild control.

I believe the initial problem was my wife's hair clogging the drain. She doesn't wash her hair in the sink either, but with her long hair she does 'shed' a few in to the sink periodically and this formed a block about 2yrs ago which I removed, but it was since then that the black sludge started. It does not occur on any other sink, though my guest bath had a resonable accumulation of mold/mildew in the DWV plumbing when I cut it loose (also black, but not sludgy like this stuff is) to remove the vanity.

Re: Odd black mold like substance in sink drain

We are the having the same issue... ours is occurring in both sinks.... we are on well water and also have a waterless tank system as well as a water conditioning system.

We are not having a problem with the other bathroom or kitchen sinks so we were thinking it could possibly be the mouthwash as well because we use it quite frequently and our kids do not. Also, it is worse in my sink and I use mine more often than my husband.

Re: Odd black mold like substance in sink drain
NEC wrote:

It is hair that feeds it.........HAIR.

The shaving cream forms a gunky slime that collects all sorts of things like hair which contributes to things growing in the drains.

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Re: Odd black mold like substance in sink drain

Soap scum, toothpaste, hair, and spittle will create the black scum especially on the stems of stoppers that are plastic.


Re: Odd black mold like substance in sink drain

Same problem with the black gook buildup in the bathroom sink, had to call plumber several times. Last time, my neighbor, who is a plumber came himself, told me he had the same problem with the black gook only on his sink, he uses Listerine. His wife didn't, and her sink was clear. I use Listerine several times a day.
Later checked with my brother, he is a chemist. He said several of the components in Listerine, probably thymol, and methyl salicylate, tend to oxidize and polimerize (translating here, so not sure of the English word). This would cause the black gunk.
Solution, the plumber neighbor uses his toilet to spit the Listerine out, I was using the kitchen garbage disposal side, however, that is now clogged, so ........ I will follow all your vinegar/salt/soda/boiling water advice posted earlier, thank you very much for all the advice !!!

Re: Odd black mold like substance in sink drain

Well, it's been almost a year since I first posted. I started NOT rinsing out my sink after I had spit Listerine in it. And, voila!~no more black mold in my sink drain. Actually, it is not listerine...it is the equate version of it in citrus flavor.:)

Re: Odd black mold like substance in sink drain

It sounds like what you are describing is a biomass. Often the initial complaint is that the water smells. What you are really experiencing is air being driven up, out of the drain into your face.

This biomass is most often found in bathroom sinks. If this is the case and you don't have it at all drains, the cause is most often make-up. Also some of the fancy soaps.

I have had to pull the trap and ream it out with paper towels to get it out. Bleach dosen't even seem to help. The only thing I have found that really works, is to take it apart and clean the trap.

Be warned. Some of that stuff can get really nasty. Wear disposable gloves and work over a garbage can.

Re: Odd black mold like substance in sink drain

I think I have the same issue in our master bath sink. Just to be sure, the stuff coming out of my sink is a black, ultra-smooth, gelatin-like substance that is perfectly formed to the drain pipe. Chunks of it come out in cylindrical shape when I take ther trap apart. Same as everyone else?

I also suspect that mouthwash is the cause. The problem seemed to begin when I began using a certain brand of mouthwash.

Anybody had good luck with the homemade remedies listed previously?

Re: Odd black mold like substance in sink drain

As most of this is generally organic matter dumping bleach down the drain periodically should help.


Re: Odd black mold like substance in sink drain

I had a nasty black buildup on the chrome sink stopper and drain opening. It was difficult to remove. I found that by switching from Listerine Total Care to Listerine Cool Mint Antiseptic mouthwash the black buildup did not return.


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