How to Repair a Running Toilet

Reaching inside and open toilet tank to adjust components.
  • 2-3 hours
  • 30-50
What You'll Need
New toilet float ball
Abrasive sponge
New flapper
Adjustable wrench
Flush valve
Tank to bowl bolts and gasket

When a toilet never seems to stop running, it can quickly drive up your water bill and get on your nerves. However, this issue can be a simple thing to fix for the average DIY enthusiast. All you will need are a few spare parts and the right advice. Start with the simplest solutions, and if those don’t work, move on to the more serious repairs.

Step 1 - Adjust the Rod or Chain

Check the guide rod or chain on the tank flapper. If the rod is bent or the chain links are twisted, simply straighten them to allow the flapper to seat completely. If this stops the water from running, there will be no need to continue.

Step 2 - Adjust or Replace the Float

Check the float mechanism next. Try lifting the ball; if this stops the water from running, bend the float arm down with pliers until you get the right buoyancy. If the ball has water in it, it needs to be replaced. You can do this easily and quickly by just unscrewing the existing float from the arm and putting a new one in its place.

Step 3 - Turn the Water Off

Locate the toilet shut-off valve behind the bowl and twist the handle to shut the water off. Flush the toilet afterward to drain the tank completely, as water can make it harder for you to inspect, clean, and replace certain parts. Always make sure to repeat this process before performing a repair if you've switched the water back on for a test.

Step 4 - Clear, Clean, or Replace the Flapper

The valve seat and flapper may be damaged or have corrosion or build-up preventing them from closing. Lift it up and check for any debris in the way first. Gently scour the seat and the rim with an abrasive sponge to remove anything that is there. If there is a great deal of damage, replace the flapper instead.

Take your old flapper with you to the store to ensure that you but a new one that with be compatible with your toilet. Attach the new one to the clips that hold the valve in place and make sure it seats properly. Open the shut-off valve again and fill the tank to test whether this stops the running water.

Step 5 - Replace the Flush Valve

The flush valve assembly may have to be replaced if your problem hasn't been fixed by this step. This involves removing the tank from the bowl completely, so take an adjustable wrench to the nuts attached to the tank bolts and try to turn them. If they prove stubborn, squirt them with a lubricant and apply a little force until they come free. Slide the bolts out of their holes and set them aside.

After pulling the tank out of place, turn it over on the towel and remove that large plastic nut in the middle. Snap a couple of quick pictures at this time if you think you will have problems remembering this set up; that way, you can consult the photos during reassembly. Remove the flush valve from the tank, take it to the hardware store, and buy a new one. If the shaft of the assembly is cracked, the whole shaft and assembly will need to be replaced instead. Install both of these pieces in the same manner as the old ones, and then put the tank back on the bowl, securing the tank bolts and washers properly.

Tip: You may want to get a new tank-to-bowl gasket, as well as new tank-to-bowl bolts. As long as you have the tank off already, you might as well change them so you don't have to worry about future leaks for a while.

When re-installing the tank, tighten the bolts one side at a time slowly with the same tension on each side. If you tighten one side too tight before you start on the other, it may crack the tank.