For the past two days, the toliet has been making a noise. I thought it was a leak, but the water isn't moving. Once toliet is flushed, the water in the tank rises all the way to the top of the overfill tube, and nearly over floater. I have watched a couple videos on youTube, but nothing they have suggested is the cause of the noise. The flapper is fairly new, and sealed. I have slide floater down to lower water line, and it doesn't work. The noise is almost like a suction sound, or water draining into a hollow spot?

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2 Answers 2


Your tank water level is too high, you need to adjust it to be lower than the level of your overflow tube (the white tube in the middle of your pic.

You appear to have a fluidmaster toilet valve (the black thing on the left) there should be an adjustment knob sticking out on an arm that can be turned by hand or screwdriver. You need to turn it counter-clockwise a few turns. After turning, test by flushing. Adjust till the water stops at least a half inch below the top of the overflow tube.

Fluidmaster water level adjustment

Picture pointing out the adjustment screw.

  • Instead of the black screwpiece as pictured, there is a straight metal stick with a clasp on it. I watched a YT video and followed it to push it down. It didn't affect water level. The water still rises to previous position even with new position of metal clasp? Oct 20, 2017 at 17:58
  • Can you update your picture to show this clasp?
    – Glen Yates
    Oct 20, 2017 at 18:46
  • updated with second picture. Oct 20, 2017 at 20:41
  • Is your float/metal clamp all the way down to the bottom of that steel wire? If it is, many of those fluidmaster valves have another height adjustment. The entire top portion of the valve turns to "screw" the height up or down. Then a finer adjustment can be made by sliding the float up and down the metal rod. Image for other height adjustment.
    – JPhi1618
    Oct 20, 2017 at 20:46

Your photo reveals that your fill hose is shoved down into the overflow tube, below the water level in the tank. This is most certainly causing a siphon action (this is a well known phenomenon to plumbers and toilet manufacturers, you can do an internet search and find lots of data). You need to pull the hose out of the tube and use a clip to aim the water stream down the overflow from above the tank water level. In @Glen Yates answer there is a photo in which you will see that the bowl filler hose is attached to the overflow tube with a clip, rather than the hose being shoved down into the tube.

You seem to have a problem with the fill-valve seal as well, since lowering the float by adjusting the clip downward on the rod should have caused the valve to shut off earlier (i.e. lower the tank level). You need to replace the diaphragm/gasket by shutting off the water to the fill valve, opening up the top by turning upper assembly 1/4 turn CCW, and replace the diaphragm/gasket, like shown in this video.

  • I went ahead, replaced the whole thing, and called it a day. Thanks guys! Oct 26, 2017 at 2:13

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