Toilet Flapper Leaking? 8 Steps to an Easy Fix [Video]

By Mengning Heil

October 15, 2021

Toilet Plumbing Tips

Reading Time: 3 minutes

If you have ever heard a toilet “flush by itself”, it is not a ghost. But, it may be an indicator that you have a toilet flapper leaking and that it’s time for a replacement. Also known as “phantom flushes,” these unnerving occurrences are actually just your tank refilling. Luckily for you, fixing a phantom flush is one of the easier plumbing projects and definitely one you can DIY. 

Toilet Flapper Leaking?

Whether you want to watch this short video or keep reading below, we have the tips you need to handle your toilet flapper leaking.

How to Fix a Leaky Toilet Flapper

  1. Choose a flapper 
  2. Locate your shut off valves
    • Before you do any work on your house it’s good to know where your emergency water shut off is just in case the toilet supply line or valve are leaking. Head back over to your toilet and turn off the water to the toilet using the shut off valve near the base of the toilet. Now you’re ready to do some work!
      toilet flapper leaking
  3. Drain the tank
    • Give your toilet a flush to drain the tank of water. If you’ve turned off the water to the toilet properly it will not refill with water.  
  4. Ditch the old flapper
    • Take the old flapper off by unhooking the chain from the lever/arm (connected to the toilet handle) and detaching it from the prongs on either side of the flush valve. 
  5. Attach new flapper
    • Attach the new flapper to the prongs on either side of the flush valve then hook the new chain up to the end of the toilet handle lever.  
  6. Adjust the chain
    • Hold the chain up to see where it hits while the lever is at rest – leave about two links of slack in the chain. You don’t want the chain too short or it will constantly pull the flapper up and allow water to leak into the bowl. You also don’t want to leave the chain too long or it will not be able to pull the flapper open all the way when you flush. You may need to adjust it several times to get it JUST right. 
  7. Turn on the water and test it out!
    • Go ahead and turn the water back on and let the tank refill with water. Once the tank is full go ahead and give it a flush to test how well it flushes. If it does not flush properly you may need to adjust the length of the chain again to make sure the flapper stays open long enough to let enough water into the bowl for a proper flush.
  8. Adjust the float (if you have one)
    • Toilet floats are made to make sure your toilet tank refills without overflowing. Many toilets don’t have floats anymore, but if yours does you may need to adjust the height of your float. Your float should sit 1-2 inches below the fill valve and the overflow tube. If your float isn’t high enough it will signal to your toilet to keep filling and cause water to run into the overflow tube and constantly stay running. 

Once you have adjusted the length of the chain on your flapper and the height of the float on the chain (if you have one), test out the flush a couple more times to make sure you have a good quality flush. If a bad flapper was the source of the phantom toilet sounds, you should not hear any more random flushing. 


Looking for a trustworthy plumber Rockville, MD? How about one who can not only assist with toilet installation but also with trickier toilet issues? Give Heil Plumbing DMV a call! Check out our Yelp, Google, and Thumbtack listings to see our five star rating across the board- you’re in good hands!


Heil Plumbing DMV is a family-run company owned by a third-generation master plumber. We can help you with a full range of plumbing services, including toilet installation and repair, leak detection and pipe repair, water heater repair and installation, faucet repair and installation, drain cleaning, water treatment, and more.