You will notice a pressure drop on the latter. There is black residue in the water heater. In either case, they are harmless to you. May 2 20What Is That Black Stuff In My Pool? It will normally look like small, dark black spots on your pool walls.
We have black water coming from hot water tap and water is.
If you look in your toilet tank and the inside is black, then you have magnesium and probably iron in the water. Black water means something corroding or building up for a long time, not a short-term issue like a clog - again assuming cold water is clear and that the water softener is on the cold water line to the house, not just hot water feed side. Apr 0 20Hot water coming out black when you first turn it on then clears. Jun 0 20Turned on my water and all of a sudden black water came out, I do have well water.
Roto-Rooter Minerals, including iron and magnesium, algae, pipe degradation and resin beads can all cause black water. Quora Jun 0 20Iaposm on a well myself, and of the time well water turns black is because A) a sludge pocket down in the water itself.