How to Fix the Flapper on Your Toilet's Flush Valve

By
Bob Formisano
Bob Formisano
Bob Formisano is a licensed architect and builder with nearly 40 years of experience building new homes and restoring older homes. One of his specialties is repairing old systems dating back to the 1920s, including galvanized water pipes, knob-and-tube wiring, and more. His home repair articles for The Spruce span more than 10 years.
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Updated on 09/04/24
Reviewed by
Richard Epstein
Richard Epstein
Reviewed by Richard Epstein
Richard Epstein is a licensed master plumber with over 40 years experience in residential and commercial plumbing. He specializes in estimating as well as design and engineering for plumbing systems, and he works for one of New York's largest union plumbing construction companies.
Learn more about The Spruce's Review Board
In This Article
Project Overview
  • Total Time: 10 - 20 mins
  • Skill Level: Beginner
  • Estimated Cost: $8 to $15
  • Yield: Fix toilet flapper

When your toilet continues to run long after you flush it, there's no need to call a plumber. In most cases, a simple, inexpensive part known as the toilet flapper is responsible for the issue. Learn how to identify and fix a toilet flapper.

Toilet handle pushed down with flush valve flapper lifting in tank
Credit:

The Spruce / Kevin Norris

What Is a Toilet Flapper?

The toilet flapper controls water in the toilet tank, either stopping it or allowing it to flow into the toilet bowl. When the toilet handle is pushed, it moves a chain, lifting the flapper and allowing water to pass.

Types of Toilet Flappers

There are two types of toilet flappers in the tank: a rubber or silicone flapper or a tank ball-style flapper.

  • Rubber or silicone flapper: Found in most modern toilets, the rubber or vinyl flapper on top of the valve lifts when the toilet handle is pressed. The flapper settles back down over the opening to seal it until the next flush cycle is initiated.
  • Tank ball: Older toilets may use a tank ball with a lift rod rather than a flapper and lift chain. The tank ball is heavy and cone-shaped. If your toilet has a tank ball, replacing it with a modern rubber or silicone flapper is usually best. Replacement kits offer a single piece that includes the flush valve, the refill tube, and the flapper in a single unit.

Before You Begin

Turn off the water when working inside the tank. Although it's possible to work without shutting off the water, it's easier if it is off. At the base of the toilet is an oval valve. Turn the handle clockwise until it stops. Flush the toilet once to empty the water from the tank.

What You'll Need

Equipment / Tools

  • Cutting pliers

Materials

  • Flapper or flapper repair kit

Instructions

Materials and tools to fix flapper in toilet flush valve
Credit:

The Spruce / Kevin Norris

Fix a Toilet That Won't Fully Flush

One problem is that you need to hold down the toilet handle for a sustained period to flush the toilet completely. When the chain has too much slack, it cannot lift the flapper enough to allow the full amount of water to flow through the flush valve; it closes prematurely, stopping the flush. Adjusting the chain's length or trimming it usually fixes the problem.

  1. Adjust the Chain Length

    Locate the chain in the toilet tank. Unhook and then re-hook the chain to adjust its length. It should have about 1/2-inch of slack.

    Flapper chain held in hand inside toilet tank
    Credit:

    The Spruce / Kevin Norris

  2. Test the Operation

    Flush the toilet. It should fully flush. If it doesn't, adjust the chain again.

    Toilet handle pushed down to test flushing
    Credit:

    The Spruce / Kevin Norris

  3. Trim the Chain

    Sometimes, the toilet chain is too long, and it hangs down. If the excess chain hangs too far, it can fall between the toilet flapper and the toilet valve. Thus, it creates an opening, never allowing the flapper to seal the valve fully.

    The fix is to use a wire cutter or side-cutting pliers to trim off the excess chain.

    Flapper chain trimmed with cutting pliers inside toilet tank
    Credit:

    The Spruce / Kevin Norris

Fix a Toilet That Continues to Run After Flushing

Sometimes, water in the toilet tank continues to flow even after the flush is completed. This is annoying and can waste up to 200 gallons of water daily.

The reason is usually that the toilet flapper doesn't tightly reseal against the flush valve, allowing water to continue to flow down into the toilet bowl. Because the tank's water level never reaches the level necessary to shut off the water supply valve (ballcock), water continues to flow.

  1. Check the Lift Chain

    Make sure the lift chain is not so long that it pinches between the flapper and the flush valve. If it is, water will leak down into the toilet bowl after the flush. Shorten the chain slightly so it doesn't get pinched beneath the flapper.

    Lift chain attached to flapper checked inside toilet tank
    Credit:

    The Spruce / Kevin Norris

  2. Align the Flapper

    Make sure the flapper is properly aligned so it seals correctly against the flush valve opening. You may be able to make small adjustments to the flapper that stop the leaking.

    Flapper aligned with flush valve opening in toilet tank
    Credit:

    The Spruce / Kevin Norris

  3. Replace the Flapper

    If the rubber of the flapper is old and cracked, it will be unable to seal the flow of water into the tank. In this case, you'll need to replace the flapper. Or, you can replace the entire flush valve/flapper assembly with a convenient repair kit.

    New flapper replaced inside toilet tank
    Credit:

    The Spruce / Kevin Norris
FAQ
  • What are common signs my toilet flapper is going bad?

    One common sign that your toilet flapper is failing is that the toilet keeps running long after you have flushed it. Another common sign of a bad flapper is that you need to hold the toilet lever for a long time to cause the toilet to completely flush. The fix is to adjust the toilet chain or replace the toilet flapper.

  • How long do toilet flappers last?

    Toilet flappers last for about five years. Even if the toilet flapper is working, it's still a good idea to replace it toward the end of its five-year lifespan to catch problems before they occur.

  • Why is my toilet still running after I fixed the flapper?

    If your toilet is still running after you fixed the flapper, the toilet chain may be preventing the flapper from sealing tightly on the toilet valve. Adjust the toilet chain or snip off excess chain to prevent the chain from falling between the flapper and the valve.

Explore more:
The Spruce uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

  1. How to Fix Your Leaky Toilet Flapper. Pinellas County (Florida) Utilities Department.

  2. The Current: Winter 2022 - WaterSense Current. U.S. Environmental Protection Agency (EPA).