Toilet Flapper Won’t Close-Causes and Fixes

If your toilet flapper won’t close and water isn’t draining properly, your home may be in for a messy time. Here’s why a toilet flapper won’t close:

Over time, debris and minerals build up around the hinges which is why the toilet flapper won’t close properly. To fix it, remove the mineral build-up from the hinges and the seal with an emery cloth. If the flapper is worn out, try replacing it with a new one.

When you flush, the toilet flapper’s function is to drain water from the toilet tank down the bowl. However, in some cases, the flapper won’t close automatically when you release the handle, resulting in leakage and water wastage.

A toilet flapper that doesn’t seal, will result in water wastage due to its inability to close properly when flushed.

In this post, I will discuss some of the common causes and solutions for a toilet flapper that won’t close.

Stay tuned!

6 Reasons Why the Toilet Flapper Won’t Close (With Solutions)

There can be a number of reasons why your toilet flapper isn’t closing. I’ll discuss each of them along with the DIY solutions. Let’s get started.

#1 Mineral Deposits Around the Toilet Flapper

If you live in a city that has hard water, the minerals’ residue will keep building up on the toilet’s flapper. This grime and deposits will cause a hindrance in closing the toilet flapper completely.

toilet flapper with mineral deposits
Image from WyattWorks Plumbing

Even if you don’t live in hard water areas, you’ll still see gunky buildups when you don’t treat toilets for a long period — Or when they are not in use.

To check if the flapper isn’t closing properly, flush the toilet a few times and see if water flows freely.

You would usually see these deposits at the bottom of the flapper, near hinges, and around the seal. The deposits look like whitish-brown crusty stains — you’ll easily recognize them lifting up the flapper.


Follow these steps to remove calcium deposits/limescale from the flapper:

  1. Turn off the water coming to the toilet with the shutoff valve.
  2. Flush the toilet to empty the toilet tank.
  3. Remove the toilet tank lid.
  4. Lift off the toilet flapper from the flush valve opening.
  5. Check the deposits around the flapper and the flush valve.
  6. Clean the mineral deposits with an emery cloth or a half-round file.
  7. Scrub gently until the obstruction is removed.

This can be done once a month for the best results.

If you fear that the flapper would break as it is too worn out or damaged, then avoid wasting your efforts. You’ll need to replace it with a new one sooner or later.

#2 Recent Rechaining Length

Have you or your plumber recently altered the flapper chain? Sometimes, when fixing the loosed chain, one may select the wrong hole in the flusher lever assembly when reconnecting the chain. This causes a changed chain length (either too short or too long) that is not enough to close the toilet flapper.

toilet flapper with chain

To see if the chain length is enough for the flapper to close, push the flapper all the way down.


Take the chain out of the wrong hole and reattach it to the neighboring hole. Keep trying again until it matches the hole for the ideal chain length. If the chain length does not match, you may need to replace the flapper chain.

#3 Short Flapper Chain Length

If the chain length is short, the flapper will unseat from the flush valve opening and won’t close all the way, causing ghost flushing.

On the other hand, if the chain length is longer than required, the flushing power of the toilet will be reduced. The flapper won’t open easily while pressing the toilet handle.

The toilet chain might also be tangled or kinked inside. Due to it, the chain length won’t be enough to seal the flapper.

Unless you’ve bought a new toilet or had recent maintenance, you won’t be facing this problem. But checking doesn’t hurt.


To fix the short-chain length, check for tangled chain areas. Remove the tangles softly and get them back to their original length.

Try flushing the toilet with the flush handle and check for the running toilet.

#4 Worn Out Flapper

If your toilet flapper has been around for a while, it might not close properly anymore because of wear and tear. Over time, this will cause the hinge to become loose which can eventually affect its ability to close completely.

worn out flapper

Old or unused flappers are might be damaged due to rust and corrosion. Despite making all the efforts, they will keep leaking the water level down to the toilet bowl.

A worn-out or defective flapper may not close completely even after repeated attempts.

When no DIY plumbing techniques are working, you know it’s time to buy a new flapper.


If the flapper is too worn out or damaged to function properly, then you’ll need to replace it with a new one. Luckily, it isn’t an expensive part and is readily available in any home improvement and plumbing store.

#5 Light Weight of the Flapper

Sometimes, flappers can be too light in weight. This can cause them to malfunction and not close properly as there isn’t enough force to push them down. When the flapper hits against the water level, it deals with a blow that eventually weakens it over time.

Oftentimes, these flappers will get displaced easily owing to their frail nature.

If you’re noticing that your toilet flapper is not closing properly, there’s a good chance that it’s because of its lightweight construction.


Nevertheless, before trying this approach, I recommend that you first clean the mineral buildup. You don’t have to change how toilet flappers work by adding weights since they are intended to close on their own.

Here’s how you can increase the weight of the flapper:

  1. Turn off the water coming to the toilet with the shutoff valve.
  2. Flush the toilet to empty the toilet tank.
  3. Remove the toilet tank lid.
  4. Disconnect the flapper chain from the flush handle arm.
  5. Add metal washers on the toilet’s flapper top until it closes completely.
  6. Reconnect the flapper chain to the flush handle arm.
  7. Close the lid back.

I would recommend replacing the metal washers every six months as they can rust due to moisture over time.

#6 Problems With the Flapper Hinge

Flapper Hinge is one of the most prone areas to hard water build-ups. This can cause the toilet flapper to malfunction and not close properly.

toilet flapper with busted hinge
Image from Cyndi Rowe Taylor

If you notice that your toilet flapper is not closing on its own, it’s likely because of a water build-up on the hinge.


To fix this issue, remove any debris from around the hinge with a brush or sponge. Flush the toilet and check if the problem remains.

Frequently Asked Question

How Do You Weight Down a Toilet Flapper?

You can use a few metal washers to weigh down a toilet flapper. Attach these metal washers at the top of the toilet’s flapper to close the flapper efficiently. You can also use any other heavy objects as alternatives to metal washers.

How Tight Should Be a Flapper Chain?

Ideally, a flapper chain should have a 1/4-inch slack when the toilet is not being flushed. If the chain is too tight, the flapper may not close properly and water could leak into the toilet.


Toilet flappers are designed to close on their own, but if they don’t, you can try a few things to fix them.

I hope this guide was helpful.

What other techniques do you use to close your flapper properly?

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