How to Fix a Leaky Toilet Flapper in 12 Easy Steps

Before you run off to the hardware store for a toilet flapper replacement part, you'll first want to inspect the toilet flapper to make sure that the flapper is the problem. Remove the lid on your toilet tank, and inspect the flapper for signs of damage. If the flapper has tears or looks deteriorated, you’ll need to replace it. Then, give your toilet a flush to see if the toilet flapper lifts and seals correctly.

If your toilet flapper appears to be in good condition but is covered in mineral deposits, algae, or debris, then you'll want to clean the toilet flapper to see if doing so fixes the faulty seal. Use a rag and a solution that dissolves minerals to wipe away limescale.

Sometimes, your toilet flapper isn't working correctly because the chain connecting the toilet flapper to the flush valve lever is faulty. This chain determines just how much the flapper lifts and shuts. If there's too much slack, your toilet flapper won't lift enough—too little slack can prevent the flapper from sealing completely. You might want to experiment with adjusting the flapper chain to see if your toilet stops leaking before replacing the flapper.

Even the most TLC in the world won’t salvage a damaged flapper. If your toilet flapper is beyond the point of saving, it will need replacing. To do this, shut off the water supply to the toilet by turning the water supply valve behind or to the side of your toilet clockwise until it can’t turn any further.

The next step is to empty the toilet tank. You can do this by holding the handle until you've removed as much water as you can from the tank.

With the tank empty and ready to go, it's time to remove your old flapper. You'll need to unhook the chain from the flush lever by unhooking the clip connecting the two parts. After you've unhooked the flapper chain, you should be able to slide the flapper from its place on the overflow tube—either over a peg or tube system—and then lift it and the chain out of your tank.

Now that you've removed the old toilet flapper, you can replace it with a new toilet flapper. Choose a toilet flapper that is compatible with your toilet’s make and model so that it fits. 

How you install your new toilet flapper will depend on the type of flapper you’re replacing. If the Overflow tube uses a tube system, then you'll need to slide the flapper over the tube before connecting the new chain to the lever. Flappers that use a peg system need the ears of the flapper to go over the overflow tube pegs before you can connect the new chain to the lever.

The flapper chain might not be ready to go straight out of the box and installation. Adjust the chain so that it has enough give without being too taut or droopy to efficiently seal your toilet tank.

After adjusting the flapper chain, you can turn on the water supply and allow the tank to fill with water. Turn the toilet’s shut-off valve counterclockwise until it can’t turn anymore.

Before you wrap up your project, test the new toilet flapper to ensure that you've correctly installed it. To test it out, give the toilet a flush. Watch the toilet flapper as you flush the toilet to see if you need to adjust the flapper chain.

If the toilet flapper chain appears loose, try shortening the length of the chain. Conversely, if the chain looks too tight as it flushes, increase the length.

Once you've correctly installed the new toilet flapper, you can consider this project a mission accomplished. Place the lid back over your toilet tank to call it a day.