How to Fix a Toilet That Has High Water

Tank and bowl water levels are controlled by different mechanisms.

Tank and bowl water levels are controlled by different mechanisms.

A toilet can have high water in the bowl or in the tank, and the remedies are different in each case. High water in the tank is usually a result of a misadjusted float, whereas high water in the bowl may be caused by a worn flapper or a waste blockage. If you're having trouble with either the float or flapper, you've probably noticed the fill valve cycling on and off or running continuously.

Adjusting the Float

The operation of the float is easy to understand, and repairs are equally simple. If you have a ballcock with a ball float on the end of a metal rod, you need to lengthen the rod to make it exert more pressure on the fill valve, shut if off sooner and lower the water level in the tank. You do that by turning the ball counterclockwise. If your float straddles the fill valve tube, it connects to the valve by means of an adjustable rod. You need to shorten the rod to lower the water level.

Servicing the Flapper

The job of the rubber flapper is to keep water in the tank until you flush. When it wears out, or the chain holding it is too short, it allows water to seep into the bowl. This makes the water level in the bowl rise to the height of the outlet of the toilet's internal P-trap. Lengthening the chain is not difficult, but it's important not to lengthen it too much or the toilet won't flush properly. When the flapper needs servicing, the best strategy is to replace it. It's easy to remove and new flappers are inexpensive.

Clearing Blockages

A blockage in the waste line can cause the bowl level to rise above the P-trap outlet, and if it's severe enough, the toilet may overflow if you don't do something. The plunger was invented for just such a situation. More often than not, vigorous plunging loosens blockages enough for them to be flushed away. Occasionally, however, a disposable diaper or tampon may find its way into the waste line. You can usually clear it with a snake, or toilet auger. You simply feed the snake directly into the bowl and crank it when it won't go any farther.


A high water level in the bowl may be a combination of a blockage and a worn flapper. You can usually diagnose a flapper problem by ripples in the bowl water and the sound of the tank refilling. These symptoms may be too subtle to detect if the leak is slow enough, however, and the higher bowl level may be the only evidence of a problem. A simple way to diagnose a flapper leak is to put food coloring or blue disinfectant into the tank and refrain from flushing for several hours. If you see the same color appearing in the bowl, it's time to service the flapper.

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