What is the mysterious hard crust in my toilet?
Mysterious hard crusts or deposits appearing in the toilet bowl or tank can look alarming, leaving people unsure whether it is mold, rust, or something else entirely. Not knowing what these deposits are or whether they mean the toilet is cracked and needs replacing makes it difficult to know how to safely remove them or whether the apartment is safe to rent.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
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What is the mysterious hard crust in my toilet?
- 1Applying acidic toilet bowl cleaner to dissolve itDid this help you?
- 2Physically removing the debrisDid this help you?
- 3Shutting off the water, vacuuming out the tank with a wet vac, cleaning it, and monitoring itDid this help you?
- 4Replacing individual worn components like rubber seals or gaskets instead of replacing the entire toiletDid this help you?
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“i’m sick right now and would deeply enjoy the use of my toilet but alas… this thing has appeared…”source ↗
“it looks kind of like a toilet paper roll unfurled but the chips that have come off it are telling me it is absolutely not that and im not sure if i can take it out! but i really must please use my toilet so i would appreciate any insight.”source ↗
“may i… remove it…? perhaps…?”source ↗
“I recently toured an apartment and saw this inside the toilet tank. Is this mold or rust?”source ↗
“Does that mean the toilet will need to be replaced soon? Would this be a red flag?”source ↗
“I did see a small crack in the toilet bowl will this be an issue?”source ↗