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Light Blue Stains in the Toilet


We have a 7-year-old toilet that has begun showing a light blue color. When I try to scrub the blue stain with a toilet brush it doesn’t come off. We’ve never used those blue tank canisters; we just use liquid bowl cleaner. Do you know why the toilet bowl is stained light blue? I checked the water (in the bowl and the tank) and it is not blue.

I also noticed a lot of black mold inside the toilet tank when I took the lid off. Is it a good idea to use bleach to clean the mold off the inside of the tank and underneath the lid? There is a rubber-type 5-inch ball in the tank. Can I use bleach to clean that rubber since it too has mold on it?


The light blue stain is a strange one. Do you have a private well? If the water is slightly corrosive, I suppose you could get a blue stain from copper or brass in touch with the water. Perhaps it is from a cleaning chemical? I would try to clean the bowl with an acid-based cleaner. Look for the acid cleaner in a plumbing supply or hardware store.

You certainly can clean the toilet tank with any chemicals you wish. Most toilet tanks will have deposits. If you do use bleach, don’t let it sit on the rubber parts because it can damage the rubber. You can remove mold with just detergent and water.