Most toilets have only 4 components that may need to be replaced if the toilet doesn’t shut off.

1.The flapper

2.The flush valve

3.The fill valve

4.The trip lever

       ①. Allow the tank to fill, then close the water supply at the shutoff valve. Mark the water level inside the tank, and let sit overnight. If the water level drops, it is either a problem with the flapper or with the flush valve.

       ②. To determine if it is the flapper or the flush valve, hold the handle down so the water level in the tank goes out to the level where the flapper and the flush valve meet. Let it sit overnight.

             a: If the water level does not drop, the problem is with the flapper. See our FAQ titled: How to replace a rubber flapper.

             b: If the water level drops to the bottom of the flush valve, where it meets the china, the gasket at the base of the flush valve is bad. See our FAQ titled: How to replace a flush valve on a two piece toilet.

      ③. If the water in Step 1 did not drop at all, the problem is most likely with the fill valve. Other symptoms that help confirm the problem is with the fill valve include: Water is going over the top of the overflow tube on the flush valve.

            a: It might be hissing or continually dripping from the end of refill tube into the overflow tube on the flush valve.

            b: If the water is not filling the tank at all, or is filling in erratic starts and stops, it is possible you have debris in the valve. For this symptom, cleaning the fill valve may eliminate the symptom.

      ④. Erratic flushing may also occur if the trip lever is wearing out. Replacement should solve the problem. See our FAQ titled: How to replace a trip lever.