I recently opened some 3/4" copper tubing before my water softener to add in a sediment filter, and was surprised to see a black greasy substance inside all of the tubing, I notice the toilet bowls get a black film inside them within a day or two after cleaning them, We sometimes have a sulpher odor coming from the hot water, my question is is it safe to use it for all but drinking water? We do have an RO system for drinking water.

1 Answer 1


Sounds like you have black sulfur. Unpleasant, but not especially unsafe. You could get a water test and know in more detail what you have in your water.

Anecdotally, I lived in a house that had a very bad case of that for a year or two, carrying in drinking/cooking water, and it was never an issue, though if I was away for a week or two the first flow of water from the pipes was solid black until it flushed itself out. I don't miss living in that house.

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