Replaced Your Toilets Flapper and It's Still Running?

Manderley Gate
by Manderley Gate
2 Materials
1 Hour

If you have a toilet keeps running even after you've replaced its flush valve flapper try this simple fix.

Universal 2" flush valve flapper repair kit

There are several different things that can cause your toilet to keep running so lets check those first.

1- Worn flush valve flapper. These can go bad after years of service and requiring replacement. NOTE: Never place any cleaning tablets in the water tank of your toilet. These can corrode the flush valve and its components causing your toilet not to function properly.

2- Clean the surface area where the flapper rests on the flush valve. This area can build up with calcium over time causing the toilet to run.

3- The water tanks fill valve is adjusted too high. If the toilets water tank fill valve is adjusted to fill the toilet too high, water will enter the overflow tube, causing the toilet to run. Make sure the filled water level is no higher than a quarter of a inch (1/4") from the top of the overflow tube. Do this by lower the float in the toilets water tank.

If you done the above items and your toilet is still running and you don't wish to replace the complete flush valve assembly (which requires removing the the water tank on a two piece toilet) try this simple fix instead.

You will need to purchase the pictured Universal 2" Flush Valve Flapper Repair Kit. (NOTE: If your toilet has a 3" flush valve you will need to purchase a repair kit for that size instead.) You will need a small piece of wet/dry sand paper, 180 to 400 grit will do. A sponge and a clean/dry towel.


Turn off the water supply to the toilet
Flush the toilet and remove old flapper
Remove excess water from tank
Sand flush valve seat area with sand paper
Clean sanded area with a clean/dry towel
Apply adhesive to bottom area of new seat
Place new seat on top of flush valve

Important: Let adhesive dry at least 15 minutes before filling water tank! I recommend a half hour or longer.

Install new flapper unit

After you have installed the new flapper unit be sure to adjust the pull chain to the handle so that flapper opens and closes all the way. This may take a few times to get it just right. You don't need water in the tank to make these adjustments.

Finish adjustments and open water supply
Test flush system several times once done

And there you have it! I've done this particular repair several times myself with great success. The alternative is to remove the toilets water tank and replace the entire flush valve assembly (which if you do, I recommend you replace the water fill valve as well) or replace the entire toilet. Hope you find this helpful and thanks for reading.

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Frequently asked questions
Have a question about this project?
3 of 17 questions
  • Joyce Hollenbach-Moll Joyce Hollenbach-Moll on Apr 30, 2018

    My problem is we need to hold the flush handle down while it flushes. What is the problem?

  • Joyce Hollenbach-Moll Joyce Hollenbach-Moll on Apr 30, 2018

    My problem is we need to hold the flush handle down while it flushes. What is the problem?

  • Doug McPherson Doug McPherson on Nov 09, 2020

    I've installed the Universal Flush Valve Flapper Repair Kit and it still leaks. What do you recommend?

Join the conversation
2 of 29 comments
  • Bucko2000 Bucko2000 on Nov 25, 2020

    Genius! My dad taught me how to fix a lot of "simple" things, but he didn't know this one. He would have loved the idea.

  • Emily Harris Emily Harris on Apr 22, 2024

    I came across a similar situation before, and it can be quite frustrating. Sometimes, even after replacing the flapper, the toilet may still run. In my case, I found that hiring a professional plumber was the best solution, apply to galaxy home recreation customer service. They were able to diagnose the issue and make the necessary repairs to stop the running. While it may seem like a simple fix, sometimes there are underlying issues that require expert attention. So, if you're still having trouble despite replacing the flapper, I'd recommend reaching out to a professional plumber for assistance.