I just had the flapper valve fail one of my home's toilets. The rubber had become spongy, sticky, and was beginning to disintegrate. It's so soft now that it rubs off with the slightest touch.

The valve was installed by the previous homeowner, so I don't know its history. However, since I've moved in, this toilet has been very seldom used. It's in the "guest" bathroom, and unfortunately have guests over now who are inconvenienced.

I'd like to understand what happened here, so I can avoid something like this happening again.

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  • 1
    I have seen flappers Soft and broken. This one takes the prize. You dont put .cleaner or CLR And leave in tank long periods of time? Reason i ask you say you do not use ,often
    – user101687
    May 28, 2019 at 5:15
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    Failure due to a combination of time and bleach or fragrances...
    – Solar Mike
    May 28, 2019 at 7:31
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    I'm going to guess that the toilet was not used much either. On my busier toilets, the seal will break down and leak before the hinge arms degrade that much. The inside of this one looks super clean.
    – BowlOfRed
    May 28, 2019 at 22:09
  • To help make the new flapper last do not put ,,cleaners ect that sit in tank long periods of time..you seem to use it for guest only.
    – user101687
    May 28, 2019 at 23:01

3 Answers 3


Your previous owner may have used those tablets in the tank that dissolve slowly and release chlorine or sodium hypochlorite (bleach). That tends to attack just about everything over time. The INTENT of those tablets is for the bleach to get down into the BOWL to help keep it clean when you flush. If you seldom flush it, the bleach tablets still dissolve slowly, but the bleach concentration just increases in the tank, which degrades the parts inside much much faster.


Flapper valves in my bathrooms typically last about 2 1/2 years of so. Depending upon the type of material they either get mushy like the ones that you show or they start to get hard and no longer make a good seal. Since I do not add anything to the toilet water tank like a disinfectant or fragrant additive I have to attribute the degradation of the flappers to the water chemistry and the chlorine that the city adds to the water.

Flapper valves are relatively inexpensive and the type you show in your pictures only take a few minutes to replace.


Chlorine. The new replacement for my model is a "Chlorine Resistant" version.

Korky Universal Flapper Premium Universal Fit Red All Rubber Seal Plus Chlorine Resistable

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