A toilet bowl with a low water level affects the strength of each flush and does not allow a thorough and efficient flush. Because of the low water level in the bowl, you may be forced to flush two or three times to force the bowl contents down the drain, which quickly becomes annoying. You can, however, fix the problem and get water back the correct level.
Remove the lid to the toilet tank. Study the level of water in the tank. If there is no mark in the rear of the tank to signify the proper water level, estimate 1 inch below the top of the overflow tube as the proper water level for the tank. The overflow tube is the vertical pipe in the middle of the tank that the flapper is attached to.
Adjust the tank's fill valve to raise the tank's water level if the water is lower than the correct amount. Adjusting your particular fill valve varies, according to the type of fill valve your tank has. Adjusting the fill valve to allow more water into the tank normally involves raising the cup on the fill valve. This will allow more water into your tank, which in turn allows more water to fill the bowl after each flush. Flush the toilet after adjusting the fill valve and check the level of water that settles in the bowl.
Examine the refill tube, which is the thin tube that directs water from the tank's fill valve into the top of the overflow tube. A damaged tube will impede this flow of water. Straighten out a refill tube that has kinks. The refill tube may also become stiff or brittle because of chemicals used in the tank. If the refill tube is too damaged to straighten, replace the tube. Connect one end of the tube to the nipple on the fill valve and connect the angle adaptor on the tube's other end to the top of the overflow tube. If no water is flowing through the refill tube at all when you flush the toilet, the fill valve likely needs to be replaced.