I have a toilet that is constantly running. Here's a photo of the inside of the tank:

enter image description here

It's hard to tell from the picture, but the water level is even with the height of the drain in the center of the tank, causing water to continually drain out (and then subsequently refill). If I pull up on the float a bit, then the filling stops as desired. However, it often gets back to the running state after a flush.

Is there an adjustment I should make to this setup, or is there a part I should replace to fix this issue?

2 Answers 2


A test first before you do anything I have suggested. when the toilet is flushed and in the process of filling, gently lift up on the gray bar that holds the blue ball to see if the water stops. If it does, it needs adjusting. If it does not, it needs replacing.

There is a screw on top of the inlet valve that adjusts the point where the water stops flowing. Screwing it in while the tank is filling 1 turn should change the water level to what you need.

Or try bending the gray metal rod that supports the blue ball so the ball sets a little lower than before, say about 1" lower, if you can manage it. Use both hands on the metal rod to bend it, the plastic valve that the rod connects to cannot take a lot of stress. That should stop the water flowing about 1", maybe less, to the top of the overflow tube.

If the water level still rises up and over the overflow tube, try the bend one more time, setting the blue ball even lower. If it still runs on, then the filler needs replaced, it is not stopping the water as it should.

Looking at the picture again, check to see if the blue ball is hitting the side of the tank, not allowing it to rise high enough to stop the waterflow. If that is the case, if there are visible threads, screw the ball in more to clear the side of the tank.


You need to replace the diaphragm (and all other gaskets) in the top of the ballcock valve (the ballcock is the fill valve with the rod and float hooked to it).

Yours is manufactured by Mansfield and you should be able to get a rebuild kit for it online or at a local plumbing shop. Mansfield manufactured several types over the years so your best bet is to bring a picture of the valve and the old gaskets with you to a good shop (notice that I deliberately did not mention any of the "big box" hardware stores). It comes apart by removing the float and rod, then unscrewing the white plastic retaining nut. Turn off the water supply first!

enter image description here

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.