Bacteria, mold and household water

I live in a house that's 91 years old. I had the pipes replaced with copper a few decades ago, but its still an old house.

Occasionally, I have to unscrew the aerator on the kitchen faucet and shake out the mineral grains. They're always red (pres. iron oxide).
This time, I wiped my finger inside the faucet itself, expecting a few more particles, but was astounded to find it lined with this ink-like substance.



Pitch black. Not slimy or gritty. Exact consistency of India ink.

Very soluble. You can see here when it drips into standing water, how easily it diffuses:

It's also very saturated with "pigment". These few drops were enough to turn the whole pan of water a sullen grey.

A little reading suggests this is manganese deposits from the water and bacteria living on the manganese. Looking for confirmation.And this is perfectly harmless?? I don't see how this isn't getting into everything we eat and drink.
(I have a drinking filter in the fridge.)That made me think about the black stuff I find in the shower stall where it doesn't get cleaned properly.

I'd always thought this was dangerous "black mold".

Are you on a well or public water system? Well water tests are not expensive and are a good idea every few years.

This is what the State of Minnesota says about manganese in water: https://www.health.state.mn.us/communities/environment/water/docs/contaminants/mangnsefctsht.pdf.

Synopsis: You won't find out from us, you need a lab test. It occurs in both private wells and municipal water supplies.

Probably a manganese slime. If it weren’t so smooth, I’d say just manganese deposits. They’re having fun! Not harmful. Sure, some of it’s getting into your water, but they tend to clump together and stay on the linings. Is this well water?

Fervent Freyja said:

Is this well water?

No. This is Toronto.

All finely divided metals and many of their oxides look black like that. Could be iron or copper.

Living in an old house can come with its quirks, right? Those ink-like substances you found inside the faucet might not necessarily be mold. It's possible that they're lubricants used in plumbing installations. However, to be on the safe side, it's a good idea to do some testing just to rule out any potential issues.

This thread is almost 3 years old....

I've seen this: it's the gasket between the pipe and the aerator disintegrating.