There are five toilets in my townhouse, three being on top floor. Exactly one of these three (always the same one) gets a visible mineral ring around the water line, while none of the other four do. All five get approximately equal use.

I'm getting tired of cleaning that one ring. Any suggestions as to why it occurs or how to prevent it from recurring?

  • You mean the visible ring is in the toilet bowl, around where the water sits when there's no on-going water usage? Most likely the air circulating through the toilet vent is causing the water level to go up and down slightly.
    – Hot Licks
    Jan 22, 2022 at 22:48
  • Why don't they coat the insides of toilets with Teflon? There would be numerous benefits. Feb 22, 2022 at 5:49

1 Answer 1


Inside the tank there could be a part that is corroding or rusting. Compare all the pieces inside the tank with the other toilets to see if there is something different.

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