How to Repair a Running Toilet 1. Adjust the Float. ... Replace the Fill Valve. If adjusting the float doesn’t do the trick, you may have a leaking fill valve might be beyond saving.

A simple float adjustment might solve the problem, or you might need to replace your flapper or fill valve entirely. When repairing your toilet, be sure to pay attention to details.

How to Repair a Running Toilet 1. Adjust the Float. The float arm controls the water level in your tank. If it’s set too high, water will keep running into the overflow tube.