Check Your Overflow Tube
The water level control valve (also called the ballcock) controls the water level inside the toilet tank. When you flush the toilet, the water level drops and the ballcock lets water into the toilet tank. The flapper then closes and the water level will rise until it reaches the preset level.
At this point, it's the control valve's job to shut the water off. If water is running down the overflow tube, the control valve needs to be adjusted or replaced.
How to check for water running down the overlow tube
Remove the toilet tank cover and look inside to see if this is where the water is constantly running. Inside the tank you should see a tube that's open at the top. Do you see water falling into the tube?
If you don't see any water falling into the top of the overflow, take a flashlight and shine it down into the tube. Do you see water moving at the bottom of the tube? If you do, then your flapper may be what's causing the water to run constantly.
What to Do if Water Is Running Down the Overflow Tube?
If you're unsure how your toilet's control valve should function or how it should look, then it's best to contact a technician to help with this job. Try Remote Assist for a free assessment before calling a tech out to your home.
NOTE: This content is for informational purposes only, and HomeX and its affiliates disclaim all liability related to it. If you decide to perform any tasks based on this information, you assume all risks, including the risk of loss or damage to property or personal injury.
Let's Get It Fixed!
Our virtual experts can diagnose your issue (for free!) and resolve simple problems.