Toilet Flapper Leaking After Replacement? (Fixed)

Oh man, that constantly leaking toilet is driving you nuts, isn’t it? 

You already replaced the flapper, but your toilet is still running! What gives? 

Well don’t pull your hair out just yet. A leaky loo after you’ve swapped the flapper is annoying, but there are a few easy things to try to fix it.

In this post, I’ll explain why your toilet flapper is leaking after replacement.

First, What is That Flapper Thing Anyway?

The flapper (also called the flush valve seal) is that little rubber piece at the bottom of your toilet tank. When you flush, it lifts up to allow the water in the tank to empty into the bowl.

Also Check Out: Compact Pulse Smart Electric Toilet with Dual-Flush Technology

Then it’s supposed to settle back down and seal off the flush valve drain hole nice and tight. 

That way, the tank can refill with water through the fill valve. 

And the cycle repeats after the next flush.

Why Is My Toilet Flapper Leaking After Replacement?

When flappers get old and worn out, they can lose their ability to make that water-tight seal on the flush valve drain. So water just keeps trickling from the tank into the bowl, and you get that  annoying sound of constant running water.

That’s why replacing the flapper is step number one when you have a leaky toilet.

But sometimes, a brand new flapper doesn’t fix the problem. Why not?

A Damaged Flush Valve Seat

In order for the flapper to seal properly, it needs to make full contact with the flush valve seat. 

This is the area at the very bottom of the tank where the flapper sits.

If the seat is damaged – pitted, corroded, or warped – the new flapper can’t make a good seal on that uneven surface.

Refill Tube Positioning 

The refill tube curves up from the valve to fill the tank after a flush.

If this tube runs too far down into the overflow pipe, it can siphon water out of the tank and cause leaks.

Also Read: Kohler Toilet Refill Tube Pops Out

Other Tricky Sources of Leaks

Sometimes the whole flush valve assembly is just plain worn out.

No flapper will seal correctly on a faulty valve.

And if the gasket around the flush valve gets folded or warped, it can also affect the flapper’s ability to seal fully. 

Too much slack in the flapper chain can make it get stuck under the flapper and break the seal.

How To Fix A Toilet Flapper That’s Leaking

Here’s what you should do if your toilet flapper leaking after replacement:

#1 Flapper Kits with New Valve Seats

Get a flapper replacement kit that also includes a new sealing ring for the valve seat from the nearest hardware store.

Once you have it, follow these steps to install:

• Shut off the water supply to the toilet.
• Flush the toilet to drain the water from the tank.
• Mark the water level inside the tank with a pencil.
• Remove the old flapper and clean the flush valve seat with steel wool, sandpaper, or an abrasive pad. Wipe away any debris and moisture from the surface of the drain seat.

Also Read: Toilet Bowl Drains Completely When Flushed

• Set the new flush valve seat repair kit upside down on a flat surface and squeeze the silicone sealant evenly around the bottom of the new seat. Use approximately ¾ of the tube.
• Center the new seat over the old drain seat and press firmly into place, avoiding getting any sealant on top of the new drain seat. Wait 15 minutes for the sealant to set completely.
• Attach the new flapper to the flush valve according to the manufacturer’s instructions.
• Connect the flapper chain to the flush lever with minimal slack.
• Turn the water supply on and let the tank refill completely.
• Test the water level in the tank; if it drops below the marked level, adjust the dial on the new seat so the next lowest number aligns with the arrow. Repeat this process until the water level drops within a half-inch of the original mark.
• Once the water level is correct, reinstall the flapper and turn the water supply on completely.

That’s it.

Now let the tank fill completely, then flush the toilet to make sure it’s functioning properly.

You can make any final adjustments to the flapper chain length if needed.

#2 Adjust The Refill Tube 

To prevent siphoning, you need to carefully reposition the refill tube so it sits higher in the overflow pipe.

To adjust the refill tube:

1. First, turn off the water supply to the toilet. 

2. Then, remove the refill tube from the overflow pipe and the fill valve. 

3. Carefully reposition the refill tube so that it sits higher in the overflow pipe. You want to make sure that the tube is not submerged in water, but also not too high that it sprays water out of the tank.

4. Once you have repositioned the refill tube, reattach it to the overflow pipe and fill valve.

5. Turn on the water supply and let the tank refill completely. Check the water level in the tank and adjust the float if necessary.

That’s it. Now flush the toilet and check for leaks.

#3 Tighten Up That Flapper Chain

Remove any excess chain slack so it can’t get stuck under the flapper and break the seal.

Wrapping Up

Some leaks require more complex repairs by a pro.

If the whole flush valve is shot, the entire assembly may need replacement. That usually entails removing the tank – not a DIY job.