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Question: Why does a ring of pinkish mold form at the water line of my toilets?
A: The rim of the toilet bowl needs to be disinfected. A ring of mold in a toilet bowl is often caused by the organisms that normally reside in the sewer; they can get to the house side of the toilet trap. They take up residence inside the rim of a toilet bowl (as well as the sink and tub overflows). The problem most often occurs during hot and humid weather. The SOLUTION is to pour several cups of household bleach into the overflow pipe of the flush valve inside the tank. This will disinfect the rim of the bowl. And you should probably disinfect the overflow drains in the wash basin and bathtub with bleach also. If the problem persists, you will have to wash down the entire bathroom in order to disinfect the whole room.