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How to Fix a Running Toilet

Beth Asaff

Running toilets sound annoying and waste a lot of water when they're left unrepaired for extended amounts of time. Learn how to fix the most common causes of a running toilet to keep it from getting out of hand.

Troubleshooting a Running Toilet

There can be several small things that cause a toilet to run, sometimes in combination. Therefore, if your toilet has been running and you've already tried jiggling the handle, take a moment to take the lid off the toilet tank and look inside to troubleshoot. You may find the solution to the problem right away, or you may need to run down the list of steps.

  1. At the bottom of your toilet tank is a rubber flapper covering up a valve that lets the water into the bowl below. If something is causing the flapper to stay open, water will continue to leak into the bowl after you flush.
  2. Put your hand into the toilet tank and press the flapper tightly against the valve. If there was something in the way like a small piece of debris, this will often free it, fixing the problem.
  3. Let go of the flapper. If the toilet stops running, put the tank cover back on. If the flapper pops back up, take a look at the chain that is connecting it to the float, or large rubber ball that is floating at the top of the water level.
  4. toilet tank
    Make sure the chain is connected to both the float and the flapper. Sometimes the chain has fallen off the float or off the flapper. If this has happened, fit the clip on each end of the chain onto the flapper or the float arm to fix the problem.
  5. Tug on the chain and make sure it is unkinked. If there was a kink in the chain, this could be causing the flapper to remain open. Sometimes running your fingers over the chain will smooth it out and allow the flapper to close. If it does, the toilet will stop running and you can replace the cover.
  6. Take a look at the float if the chain is connected and the toilet is still running. Make sure it isn't pressed against the side of the toilet tank, preventing it from rising completely. If it has migrated to the side, gently twist it back to the center of the tank to see if this fixes the problem.
  7. Look at the surface of the float itself. Make sure it doesn't have any cracks or holes that could be causing it to fill with water and sink, keeping the flapper open. If there are cracks, unscrew the float from the end of its arm by turning it counterclockwise until it comes out. Take it to the hardware store and buy an identical replacement. Screw it onto the arm and adjust the arm as in the next step.
  8. Take a look at the tower that the float arm connects to. At the top is a screw that adjusts the float. Sometimes the float can get out of balance, which causes the toilet to run.
  9. Get a screwdriver that matches the type of screw on the tower and try turning the screw a few degrees in each direction to see if this stops the toilet from running. Give the screw a small turn at a time and pause to see if the problem is solved before continuing to turn the screw.

If none of these easy fixes solve the problem, it's time to remove and replace your valve and flapper.

Replacing a Toilet Valve

This is a fairly straightforward job for one person to take on by themselves. If you are uncomfortable with the procedure, however, most plumbers can make the fix in under an hour.


  • Adjustable pipe wrench
  • Measuring tape


  1. Locate your toilet's fill valve at the wall near the bottom of the toilet. Shut off the water to the toilet.
  2. Take off the toilet tank and hold down the flush handle to drain as much water from the tank as possible.
  3. Sponge out any remaining water from the tank.
  4. Take a look at the underside of the tank where the hose that connects the valve is located. Unscrew the fill hose from the tank using the wrench.
  5. Unscrew the nut that holds the fill valve to the tank. It will be located beneath the tank near where the hose had been connected. Remove the nut and set it aside.
  6. Lift the fill valve out of the toilet tank.
  7. Take the valve with you to the hardware store so you can get an exact replacement.
  8. Set the new valve into the tank.
  9. Check the instructions on the new valve. It will tell you what height to set the valve at. Use your measuring tape on the interior of the tank to get the valve to the correct height.
  10. Screw the nut on below the tank to hold the valve in place at the correct height.
  11. Connect the chain that will hold the new float to the flapper and push the flapper down into place.
  12. Reattach the water supply tube to the underside of the tank.
  13. Turn on the water valve to fill the tank.
  14. Flush the toilet to ensure it works and to check for leaks.
  15. Replace the lid on the tank.

Stop Running Toilets

Running toilets can waste a lot of water over time if they aren't fixed. Take the time to troubleshoot and repair this problem as soon as you notice it and stop your toilet from running.

How to Fix a Running Toilet