The water in the toilet in my guest bathroom has been running on and off by itself for the last couple of weeks. At first, I was convinced the cause was paranormal activity. Shortly after though, I decided, ghosts or no ghosts, I was going to take a look.

The problem turned out to be a worn out flapper valve. No ghosts. Phew! Worn out flappers are one of the most common reasons why toilets run after use.

The rubber flapper valve lifts when you flush the toilet to let water flow into the bowl. As the bowl fills, the water in the tank empties and the flapper valve sinks down to block the opening, allowing the tank to refill once more. When a toilet flapper wears down, it does not create a watertight seal. A steady trickle of water is allowed to flow through the opening and into the bowl. The result is an audible trickle of water as well as the occasional surge of water to top off the valve.

Below is our easy step-by-step walkthrough on how to replace a toilet flapper valve.

Tools Required

  • Scissors

Materials Required

  • New Toilet Flapper

Time Required

  • 5 Minutes

Difficulty Level

  • Easy

Select the Right Flapper Valve

There are a few different types of flapper valves out there. However, a universal flapper valve – available for $5 to $10 bucks at your home improvement store – should do the job on most toilets. If you want to be one hundred perfect sure, take a quick look at your old flapper valve before heading down to the shop to pick up a new one so you know exactly what you’re shopping for. Replacing a toilet flapper isn't like replacing a water main or anything... it's actually quite easy!

1. Drain Tank

Your first order of business is to drain your toilet’s tank. Start by turning the water to the toilet off. Do this by turning the handle of the water supply valve (normally located on the back wall to the left of the toilet) clockwise. Then flush the toilet to drain the tank of water. No water will fill it back up since you just turned the water supply off.

2. Remove Old Flapper

Remove the tank cover. Then unhinge the old flapper’s chain from the toilet handle rod. Slide one side (or ear) of the old flapper to the side and pull it free from the flush valve. Pull the other side of the flapper free.

3. Prep New Flapper

Almost all relatively newish toilets have the same flapper configuration (L-shaped ear attachments). This requires you to cut the ring piece off of your new flapper with a pair of scissors. The back of the packaging your new flapper came in should have a diagram of exactly where to cut the ring at.

4. Install New Flapper

Now that your new flapper valve is prepped, it is time to install it to the flush valve. It slides on in basically the same way you took the old one off. Each side ear hooks into place on either side of the flush valve.

Once secured, hook the chain back onto the toilet handle rod. You’ll likely have to make some adjustments to the length of the new chain. It should be long enough for the flapper to sit securely in place but short enough to actually lift it up when flushed.

5. Test It Out!

Turn the water back on by turning the water supply valve counterclockwise. Give your toilet a flush or two to make sure it is in working order. Your running toilet problem should now be fixed!

Final Thoughts on Replacing a Toilet Flapper

A worn out flapper is one of the most common reasons why a toilet runs while not in use. This quick little how-to project will have your toilet running perfectly again in little time at all. If the problem persists when maybe it's time to call a plumber.