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Repair a Leaky Toilet

Even a small leak can waste a significant amount of water over time. Use this guideline to make sure your toilets are working properly and not wasting water.

Illustration of toilet components

It's not always easy to tell if your toilet is leaking. To check for a slow leak, add some food coloring or dye tablets to the water inside the tank and wait 5 to 10 minutes. If the color seeps into the toilet bowl, you have a leak. To repair the leak, follow these steps:

  • Step 1: Remove the tank lid and check the float arm. Reach in and lift it up. If the water stops running, you've found the problem. Adjust the screws or bolts to the inlet float valve until the water stops flowing.
  • Step 2: If the toilet continues to leak, turn off the water supply valve to the tank, and flush the toilet to drain out the water. Examine the inlet float valve by removing the two screws or bolts and lifting the top of the valve housing out. Check the diaphragm. If it’s slightly damaged or worn, replace it.
  • Step 3: If the toilet periodically refills without flushing, examine the ball stopper or flapper valve. It should fit flush in its seat. If not, look at the lever and guide rods that operate the ball stopper. If they are crooked, gently straighten them. For toilets with a chain pull attached to the flapper valve, make sure the chain is slack when the valve is seated to ensure a snug fit. If the ball or flapper valve itself is worn out, replace it. Check for corrosion or deposits on the seat and the ball stopper or flapper valve. Use steel wool to remove this buildup.
  • Step 4: Inspect the small refill tube that connects the fill valve to the refill-overflow tube to be sure the smaller tube ends slightly above the standing water level of the filled tank. If necessary, gently pull the small tube upward until its end is correctly placed.
  • Step 5: If the toilet is still leaking, you may have a problem with the fill valve. In this case, a steady trickle of water will run constantly, flowing into the overflow tube in the toilet tank. If the water level in the tank is up to the top of the overflow tube, you probably have a fill valve problem. First, try to adjust the float level so the water stops flowing before reaching the overflow level.
  • Step 6: If that doesn't stop the leak, replace the fill valve. Shut off the water supply to the toilet and flush to empty the tank. Sponge the final few cups of water from the bottom of the tank. Disconnect the supply line, and remove the nut on the bottom of the tank to remove the old fill valve assembly. Install a new fill valve assembly and reattach the supply line. Finally, attach the fill tube hose to the overflow tube. Turn the water back on, and adjust the float so that the water shuts off about 1 inch below the top of the overflow tube.

Note: If your toilet has a Fluidmaster valve instead of a float arm, refer to the Fluidmaster website for more information.