A properly functioning toilet provides an efficient and convenient way to dispose of human waste. Within the toilet is a flapper valve that holds water in the tank until flushed. If a flapper valve closes too soon, the toilet can flush incompletely. Some minor adjustments to the toilet may help fix this problem.
The flapper valve in a toilet holds the water in the tank until the flush handle is depressed. The handle activates a lever in the tank that is attached to the flapper valve with a stainless steel chain. When flushed, the valve raises up, trapping air within it so that it floats, allowing the water to run out of the tank and into the toilet. When the tank is empty, the valve drops back in place to seal the tank again, while the fill valve fills the tank with water.
Examine the flapper valve for damage, such as worn edges or tears on the valve material. When the toilet is flushed, a damaged valve may allow the air trapped within it to escape prematurely, causing the valve to fall too soon. If the flapper valve is worn or damaged, replace it.
Locate the fill line on the overflow tube in the toilet tank. Adjust the float on the fill valve in the toilet tank by bending the metal rod to the float upward or setting the float cup to a higher shut-off height, depending on the model of fill valve in the toilet. Set the float or cup to allow enough water to fill the toilet tank to hold the flapper valve up when flushing the toilet.
Shorten the length of chain from the flush handle lever to the flapper valve. If the chain is too long, the valve will not raise up completely to trap sufficient air under the valve. A shorter chain from the lever to the valve pulls the flapper up completely, giving it sufficient float time to allow the toilet to flush properly.