Plumbing Hollywood

How to Fix a Running Toilet Tank

running toilet tank

Fix Your Running Toilet Tank

Some people will call us and say “Sunshine Plumbing of South Florida Inc, please help us! Our toilet is running, what should we do??” to which our response is usually along the lines of “well first you should go and catch it.” Then after the embarrassment and cricket sounds subside, we’ll probably tell you to check three things in your toilet tank: your chain, your flapper, and your float ball/cup. Read on to learn more about these fixes so that you can repair your running toilet tank, because you and I both know that plumbing problems are no joke.

Fix #1: Check the lift chain.


So the first step is to pop open the lid of your running toilet tank and take a look around to try and diagnose the problem. One of the more obvious and glaring problems that lead to a running toilet tank is that the chain gets stuck in the flapper. This happens when the chain is too long and has too much slack in it. When the lever is pulled and the toilet flushes, the chain is stretched straight out as it opens the flapper, but if it has too much slack, once you drop the lever, releasing the chain, the over lengthened chain will fall in the way of the descending flapper ball. If the flapper doesn’t close all the way then water will continue to spill down the hole, wasting tons of water.

To fix this, all you have to do is simply take the hook that attaches the chain to the flush lever, slip it off the link that it is currently on, and move it to a lower link. The new link that you choose matters. Having too little slack and too straight of a chain will prevent the flapper from closing, and of course too much slack will just have you back at square one. You still want a little bit of slack left so that the flapper has enough room to close, but not so much that it gets in the way.

Fix #2: Check the flapper.


A very common reason your toilet may be running, especially for older toilets, is that the flapper has worn away. Flappers get put through a lot of wear and tear and need to be changed out every once in awhile. A deteriorated flapper will fail to seal the Douglas valve properly, once again allowing water to spill through. This can be fixed relatively easily by taking a trip to the home improvement store, grabbing a new flapper for about $5 and swapping out the old with the new.

To replace a flapper, begin by turning off the water supply to your toilet and flushing the toilet so that you have some dry space in the tank to work with. Unhook the chain from the lever and disconnect the flapper from the two sides of the flush valve. Then, after discarding the old flapper, work in reverse to connect the new flapper to the pegs on the two sides of the flush valve, and reattach the chain to the lever, keeping in mind to use the appropriate amount of slack.

Fix #3: Check the float ball or float cup.


If the problem with the running toilet tank isn’t water spilling down the flush valve as with the two scenarios mentioned earlier, then the water might be spilling down the overfill tube. If the water level is above the overfill tube then the toilet will just keep cycling more and more water to the tank. The water level needs to be set below the overfill tube, and this can be done adjusting either the float cup or the float ball, whichever your toilet has.


Newer toilets tend to have overflow cups that wrap right around the fill tube. If the cup is too high then you can lower it by locating the screw on the cup and screwing it counter clockwise, lowering the cup. You want the water level to be about 0.5”-1” below the top opening of the overflow tube, so adjust accordingly. If your toilet has a ball float that stems from the fill tube you can lower this as well by just loosening the screw that holds the ball in place. Loosening the screw will cause the ball the drop, effectively lowering the water level.

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