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Tips for the Repair of a Kohler Toilet That Runs

Steven Symes

A Kohler toilet will normally run only after you have flushed it; it will stop once the tank has filled completely with water. A running toilet not only causes a nuisance, but it also wastes water as it increases your water bill. Several problems can cause your Kohler toilet to run, all of which you can fix yourself.


Before you begin to replace any parts or make adjustments to your Kohler toilet, first determine the source of the toilet running by performing a simple test. Remove the cover from the toilet’s tank, and wait for it to stop running. Add several drops of food coloring to the water in the tank; the darker the food coloring, the better, and wait to see where the food coloring travels. If the food coloring heads straight for the black rubber flapper valve in the bottom of the tank, you need to remove the old flapper and insert a new one.

Float Valve

Food coloring running down the tall plastic tube inside the toilet’s tank indicates that the water level inside the tank is too high. The only way to correct the problem is to adjust the height of the tank’s float valve. On some Kohler toilets the valve is a large plastic ball attached to a metal rod. You must bend the metal rod down to lower the ball, which will cause the tank to fill with less water. Other Kohler toilets have a float valve that slides up and down on a metal rod. You can adjust these valves by pinching the clip that attaches the valve to the rod, and slide the valve down the rod before releasing the clip. Take care not to lower the float valve too much; otherwise you will have problems with the toilet not flushing all the way.

Chain Adjustment

Check the chain that attaches to the handle on the outside of the tank as well as the flapper valve. The chain should not have more than one or two links worth of slack once the flapper valve is closed. Use needle-nose pliers to adjust the chain to the appropriate amount of slack.


Sediment will often be kicked up and introduced into a house’s plumbing when the water in the area is shut off. Turning the water off just in your house can also stir up sediment that otherwise would sit stationary. Remove the cap on the top of the fill valve in the toilet to check the diaphragm seal for sediment. Flush out the diaphragm with a steady stream of water, and replace it in the fill valve. If flushing the diaphragm seal does not work, you will need to install a new one.