How to Fix a Running Toilet
Stop the constant flow of water and save money on your water bill by diagnosing and repairing a running toilet.
Step-by-Step Instructions
Diagnose the Problem
First, listen carefully. Is water running constantly, or does it cycle on and off every few minutes? Lift the tank lid and look inside. The most common culprits are a worn flapper, a misaligned chain, a faulty fill valve, or a leaking tank-to-bowl gasket.
Test for a Silent Leak
Add 5-10 drops of food coloring into the tank water. Wait 15-20 minutes without flushing. If colored water appears in the bowl, your flapper is leaking and needs replacement. This is the most common cause of a running toilet.
Turn Off Water and Drain the Tank
Turn the shut-off valve clockwise behind the toilet to stop water flow. Flush the toilet and hold the handle down to drain as much water as possible from the tank. Use a sponge to soak up any remaining water in the bottom of the tank.
Inspect and Adjust the Flapper Chain
Check the chain connecting the flush handle to the flapper. It should have about half an inch of slack — too tight and it will not seal; too loose and it will not lift the flapper fully. Adjust the clip on the chain to get the right tension.
Replace the Flapper
Unclip the old flapper from the flush valve ears and detach the chain. Take it to the hardware store to match the size (2-inch or 3-inch). Install the new flapper by hooking the ears onto the flush valve pegs and connecting the chain with proper slack.
Check the Fill Valve and Float
Turn the water back on and let the tank fill. If water rises above the overflow tube and spills into it, the fill valve is not shutting off. Adjust the float by turning the adjustment screw or sliding the float clip down to lower the shut-off water level.
Replace the Fill Valve (If Needed)
If adjusting the float does not fix the overflow, replace the fill valve. Disconnect the water supply line, remove the lock nut under the tank, and pull the old valve out. Install the new valve, tighten the nut hand-tight plus a quarter turn, and reconnect the supply line.
Inspect the Tank-to-Bowl Gasket
If you see water pooling around the base of the toilet, the tank-to-bowl gasket may be leaking. Turn the water off, drain the tank, disconnect the supply line, and remove the tank bolts. Replace the rubber gasket between the tank and bowl, then reassemble.
Turn Water On and Test
Turn the water supply back on counterclockwise and let the tank fill. Flush several times and observe. The tank should fill to about an inch below the overflow tube, then stop completely. There should be no hissing, trickling, or cycling sounds.
Final Leak Check
Do one more food coloring test to confirm there are no silent leaks. Wipe down the tank exterior and check the floor around the base for any dampness. A properly fixed toilet should be completely silent between flushes and save you real money on water.
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