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toilet tank overfilling

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  • toilet tank overfilling

    Does anybody know what could cause a toilet tank to overfill when it hasn't been flushed for a few hours? The toilet itself isn't running but water keeps entering the tank. When we get up in the morning and the toilet has gone unflushed for the whole night, we always have water that has dripped into the pail overnight. It appears that the tank continues to fill up during the night and water is dripping out from the hole that the handle comes out of. The dripping will continue until it's flushed again. As long as it's flushed often throughout the day there is no problem. I didn't even realize water could keep coming into the tank if it wasn't actually running. Any ideas? Thanks in advance.

  • #2
    This is a common problem. The tiny little needle valve in the fill valve mechanism is not sealing completely so an extremely slight amount of water continues to enter the tank even though the valve is closed.

    It also sounds like you have had to change the flush valve at some time in the past and the new flush valve standpipe is slightly too tall, otherwise the excess water would be spilling over the top of the standpipe and going into the bowl rather than leaking out the flush handle opening.

    You might have some success by adjusting the fill valve float arm to stop the water a bit lower in the tank. (There should be a water level index line printed or embossed on the tank wall) This may be enough to completely close the valve and stop the slow leak. Otherwise you will need to either rebuild your existing ballcock fill valve assembly or replace it.

    Unless you have a toilet that has a radically different style of fill valve, i would suggest replacing the fill valve with a Fluidmaster universal fill valve kit, which is available at all hardware stores for about $10. The fluidmaster unit is a complete kit with all necessary parts and very good illustrated directions. This is a simple DIY job that should take about 20 to 30 minutes and all you will need is a good pair of pliers.


    • #3
      thanks for the response. i live in an apt. but maintenance is so slow to respond to these kinds of issues i figured i'd just try to do it myself. i just looked in the tank and it looks like they have already replace the original fill valve with the fluidmaster universal (model 200A). your diagram shows a final water level adjustment clip. does that mean if i move that clip it would have the same effect on the water level as bending the float arm on the original set up? i can't figure out how to adjust the water level with the fluidmaster since there's no arm to be bent and lowered. thanks again.


      • #4
        ON the fluid master float if you pinch the clip you can slide the float up or down the shaft to whatever point you desire.I would suggest you try sliding it down about 1/2", then flush the tank and watch it refill, see if it stops at the indexed water level, if not repeat the adjustment proceedure.


        • #5
          thank you so much! now i feel like an idiot considering how simple that was. whoever installed the fluidmaster had the water level above the indexed line. so that in addition to the extra water coming in and the standpipe being too tall were all contributing to the drip. your help is greatly appreciated.


          • #6
            Only one thing left to do Sam,,,write a small bill for a plumbing service call, drop it in the household budget cookie jar, grab the cash and your significant other and go out to dinner (No one should work for free)


            • #7
              ok, I have another question on this one. although i've been able to adjust the float enough to keep the tank from leaking overnight, we still have a slow leak so if we're gone for more than a day we come back to a pail full of water. our apt. maintenance guy is not quick to respond to these types of issues. we are actually moving soon and don't want to be held responsible for any type of damage that may happen as a result of them not fixing this before we move so i figured i'd just turn off the water to the toilet and fill them in as to why. well, i turned the water valve by the toilet all the way off but water still comes into the toilet when i flush. have you ever heard of this before or have any idea why it would still be filling when the water supply has been turned off? i guess there could be something wrong with the water supply valve itself, but i'm hoping my bad luck hasn't extended that far. thanks in advance for your input.


              • #8
                Toilet tank fill problem

                My tank, like that of quite a few others it seems, continues to fill to the point of overflowing if I don't cut off the water input at the source (at the valve below the toilet on the bathroom wall). The odd thing about my toilet though is that the tank continues to fill (very slowly) even after the float has risen and no further water is exiting that rubber tube that runs from the float assembly into the vertical center piece (tube) in the tank. I hear no running water and I see no ripples in the tank that might suggest running. All I can think of is that there is some kind of leak in the float stand assembly. However, the one I have is almost brand new. This problem began after I removed the toilet and replaced the wax seal that was leaking from under the toilet onto the floor. So that's fix and no longer leaking, but now I have this new problem, as described. In removing the toilet (with the tank attached and the valve assembly in place), I did have occasion to turn the entire toilet upside down. I'm wondering if that upside down position could cause a problem with the float valve assembly. Would appreciate any constructive input. My next step will be to replace the float valve assembly.


                • #9
                  Replace the fill valve as it is the only component that allows water to enter the tank therefore it isn't working....
                  I stayed at a Holiday Inn Express last night.
                  Now I can Plumb!

                  For great information on the history of sanitary sewers including the use of Redwood Pipe
                  Did you know some Redwood Pipe is still in service today.