Thread: Black Toilet Tank

I inspected two homes today, separated by 300-400 feet. Both homes share a well and all of the toilet tanks have black coating up to the water line. I have seen this in tanks before and thought it was some type of mold. In the newer home, which has PEX, I noticed that some of the white PEX pipe was dark or gray, suggesting that whatever was causing the tanks to turn black was in the pipes as well. No complaints from the home owner about water taste, odor or laundry problems. I asked the lab doing the water test what it might be and they had heard that it might be due to managanese in the water. Has anyone had this problem and what did you find?

Manganese is a likely cause. They should install a specialized filter system.

Water quality information - Water Problems ? Manganese | APEC Water

Originally Posted by John Kogel

Manganese is a likely cause. They should install a specialized filter system.

Water quality information - Water Problems ? Manganese | APEC Water

thanks John, good link. I'll let you know what the lab results are.

Originally Posted by Vern Heiler

thanks John, good link. I'll let you know what the lab results are.

Manganese result is 0.39 EPA limit is 0.50. Don't know what the health risk is but now know what makes toilet tanks and PEX lines black.