Leaking Toilet Flapper? Here’s How To Fix It in 4 Steps!

Is the incessant noise from your leaking toilet flapper keeping you up? And is it the noise or the wasted water that bothers you most?

Have no fear, sanity is on the way. We’re going to show you how to replace or clean your leaky toilet flapper valve so you can finally get some peace.

What Does a Toilet Flapper Look Like?

The flapper valve is a large rubber (or hard plastic) seal located in the middle of the bottom of your toilet tank.

It is usually attached by a chain to an arm that’s connected to the toilet’s handle. When the handle is pressed, the arm lifts the chain and opens the flapper. Once opened, water rushes into the toilet bowl creating your flush. When closed, no water should be able to get through.

Leaky Toilet Flapper - Diagram
Use this diagram to better understand what your leaking toilet flapper valve looks like and where to find it.

Fix Your Leaky Toilet Flapper in 4 Steps

You’ll be surprised how easy it is to clean or replace a leaking toilet flapper valve. To get started, you’ll want to have the following items on hand:

  • Old towel
  • Mineral-removing cleaner
  • Screwdriver
  • Pliers
  • Replacement flapper (if needed)

1. Determine if Your Flapper Valve is Leaking

Firstly, start by putting a few drops of food coloring into your toilet tank.

Don’t flush. Just wait a few minutes. If the water turns color, then you’ve got a leak coming from the tank into the toilet bowl. And if your toilet is leaking, the probable cause (the most common, in fact), is a worn flapper valve.

By the way, the second most common reason for a running toilet is a problem with the fill valve (we’ll discuss that solution in another article to come).

Leaky Toilet Flapper - add food coloring to tank
Add food coloring to your tank, wait several minutes, then see if any coloring has leaked into your toilet bowl. If so, you probably have a leaking toilet flapper.

2. Turn Off Your Water Supply

The best way to turn off the water for small repairs is to carefully turn off the supply valve to the faucet or toilet. (If plumbing repairs require that the water be shut off for the whole house, best to get your plumber involved.) But for this job, just turn off the water supply valve for the toilet.

The supply valve is usually located under the lower-left part of the toilet tank. Use caution when turning the handle as these are notorious for breaking off. Have a towel handy to soak up any drips. Flush the toilet so that water drains out of the tank.

Toilet failure shut-off toilet water supply line
The water shutoff valve for the toilet (not the rest of the house) is located against the wall, on the left side of the toilet underneath the tank.

3. Clean or Replace the Flapper

Take off the lid of the tank and check the flapper valve. Make sure it’s clean and smooth.

Option 1: Clean Your Leaking Toilet Flapper

If it’s dirty or has a buildup of minerals or algae on it, the flapper may not be able to seal properly. (Heck, while you’re at it, make sure that the tank itself is clean and smooth as well.)

If either the toilet flapper or the drain has any buildup on them, simply clean them with an old rag and, if necessary, a mineral-removing liquid such as Lime-A-Way. Make sure to follow the manufacturer’s recommendations.

Leaky toilet flapper - dirty flapper
A dirty flapper can cause a leak due to algae or other minerals not allowing the flapper to properly close.

Option 2: Replace Your Leaking Toilet Flapper

If the flapper is dried out, warped, cracked, or pitted, then you’ll need to replace it.

Check for cracks in the flush valve (the piece the toilet flapper seals against). Cracks seldom appear here, but if they do, you may need a whole new toilet if the part cannot be found or the toilet is too old. The silver lining, in this case, is that the newer toilets may save you enough water to pay for the replacement.

Leaky toilet Flapper - replace flapper
Replacing the flapper with a new one is actually quite easy.

4. Check the Flapper Chain

Before you replace the tank lid, check the chain that links the toilet flapper to the arm.

Make sure there is some slack in it. If it’s too tight, it can hold the flapper open enough to allow the leak to persist. If there is too much slack, the chain can get caught between the flapper and the drain.

Here’s a related article – How to Replace a Toilet Handle – A Step-by-Step Guide — that provides detailed steps on connecting a flapper chain (and much more).

Step 6 How To Replace Toilet Handle Attach Chain
When reconnecting the flapper to the chain, it’s important to make sure it has just a bit of slack in it…but not too much. You can experiment and see which hole of the arm provides the right amount of slack.


Here are more great resources related to fixing your toilet:

Final Thoughts

Here’s the good news. In most cases, a leaking toilet flapper valve is easy to clean and replace. Simply following this small handful of instructions will have your toilet running smoothly in no time.

For a detailed video on the two most common causes (and fixes) of a leaky flapper, check out this video on fixing a leaking toilet flapper.

Call 1-Tom-Plumber

Don’t hesitate to contact or call us at 1-Tom-Plumber (1-866-758-6237). We will immediately handle any emergency plumbingdrain, and water damage problem, including excavation of underground water lines and sewer main lines.

And if you need help fixing or replacing your toilet flapper valve, we’ll do that too!

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