A flapper replacement takes one person, one inexpensive part, and basic tools you likely own

The flapper is a rubber or plastic disc at the bottom of your toilet tank that lifts when you flush, lets water rush into the bowl, then seals again to refill the tank. When it wears out — usually after three to five years — water leaks slowly into the bowl, your toilet runs constantly, and your water bill climbs. Replacing it costs between $5 and $15 for the part itself and takes about 15 minutes. You do not need a plumber.

The job requires only a screwdriver or wrench, a bucket or towel, and the new flapper. You will turn off the water, empty the tank, unclip the old flapper, and snap the new one in place. The hardest part is finding the right flapper model for your tank, because different toilets use different sizes and attachment styles.

Key Takeaways

  • Turn off the water at the shutoff valve behind or below the toilet, then flush to empty the tank before you touch anything inside.
  • The flapper sits at the bottom center of the tank, held by a clip or chain; take a photo of it before removal so you can match the replacement exactly.
  • Bring the old flapper to a hardware store or take its photo to the store, because flapper sizes and attachment methods vary widely between toilet models.
  • The new flapper clips or screws into place in seconds; test it by filling the tank and listening for water running into the bowl after the tank is full.

Turn off the water and empty the tank

Locate the shutoff valve on the water line behind or below the toilet. Turn it clockwise until it stops. If you cannot find it or it will not turn, you can still do the job — just work carefully and have a bucket ready to catch water.

Flush the toilet once to empty the tank. If the water does not drain completely, use a cup or sponge to remove the remaining water and place it in a bucket. Wipe the inside of the tank dry with a towel so you can see clearly.

Locate and photograph the old flapper

Look at the bottom center of the tank. You will see a rubber or plastic disc (the flapper) connected to a chain or rod that runs up to the flush handle. The flapper sits on a rubber or plastic seat and seals the hole that lets water into the bowl.

Before you touch anything, take a clear photo of the flapper from above and from the side. Note whether it is held by a clip on a rod, screwed to the seat, or connected by a chain. This photo is your shopping list — flapper designs vary, and buying the wrong one means a second trip to the store.

Remove the old flapper

If the flapper is clipped to a rod, squeeze the clip or unscrew it by hand and slide the flapper off. If it is screwed down, use a screwdriver to remove the two screws holding it to the seat. Keep the screws in a small cup so you do not lose them.

Lift the flapper out of the tank. If it is stuck, soak the area with a little water and wait a minute, then try again. Inspect the rubber seat underneath — if it is cracked, rough, or heavily stained, you may need to replace that too, but most of the time a new flapper alone solves the problem.

Buy the correct replacement flapper

Take the old flapper or your photo to a hardware store or home center. Show it to a staff member in the plumbing section and say "I need a replacement flapper for this model." Flappers are sold individually and cost between $5 and $15. Common brands include Korky, Kohler, and Toto, but the store will have universal options that fit most tanks.

If you order online, search for your toilet brand and model number (usually stamped on the tank or bowl) plus the word "flapper." Read the product description carefully to confirm it matches your old one. Universal flappers exist, but they do not fit every tank, so matching the original is safer.

Install the new flapper

Position the new flapper over the hole at the bottom of the tank, aligning it with the seat. If it clips to a rod, slide it onto the rod and tighten the clip by hand or with a screwdriver. If it screws down, line up the holes and insert the screws, tightening them firmly but not so hard that you crack the plastic.

Make sure the chain or rod is not twisted and has a little slack — about half an inch — when the flapper is closed. If the chain is too tight, the flapper will not seal. If it is too loose, the toilet will run. Adjust the chain by moving its attachment point on the flush handle arm, or by removing a link if it is too long.

Test the flapper and turn the water back on

Turn the shutoff valve counterclockwise to restore water flow. The tank will fill. Once it is full, listen for water trickling into the bowl. You should hear nothing — silence means the flapper is sealing correctly.

Flush the toilet and watch the flapper lift and fall. The bowl should empty completely and the tank should refill without running water afterward. If water still trickles into the bowl after the tank is full, the flapper may not be seated correctly. Turn off the water, check that the flapper is centered on the hole, and try again. If the problem persists, the rubber seat may be damaged and need replacement — a job that requires a seat repair kit and takes about 30 minutes.

Frequently Asked Questions

How do I know if my flapper is actually broken?

The most common sign is a toilet that runs constantly or refills on its own without being flushed. You may also hear a faint hissing sound coming from inside the tank. To check, add food coloring to the tank and wait 10 minutes without flushing — if the color moves into the bowl, water is leaking past the flapper.

Can I use a universal flapper instead of matching my old one?

Universal flappers work in many toilets, but not all. They are cheaper and faster to install if they fit, but if yours does not work, you will have wasted money and time. Matching the original is the safer choice, especially if you are not sure about your toilet model.

What if the flapper still leaks after I replace it?

The rubber seat under the flapper may be cracked or worn. You can buy a seat repair kit at a hardware store for $10 to $20 — it includes a new rubber seal that sits on top of the old seat. If that does not work, the tank itself may be cracked, which usually means replacing the entire toilet.

Do I need to turn off the water to replace a flapper?

No, but it makes the job cleaner and safer. If you do not turn off the water, flush first to empty the tank, then work quickly and have a towel ready to catch any water that remains. Turning off the water takes 10 seconds and prevents accidents.

How often do flappers need to be replaced?

Most flappers last three to five years before the rubber hardens and stops sealing. Hard water and chlorine in the water supply can shorten that time. If your toilet runs frequently, replacing the flapper every few years is normal maintenance.