A toilet's flushing mechanism consists of the handle, which is visible from the exterior of the toilet, as well as several interior parts. When the handle is engaged, it lifts the flapper out of the hole in the bottom of the tank to release the water in the tank into the bowl to flush out the material. The flapper connects to the handle via a chain and a flush lever arm. When a toilet will not flush, the cause is usually a broken or disconnected chain.
Lift the lid off the toilet tank and set it aside. Locate the shut-off valve under the toilet, generally by the floor on the left side. Turn the handle or knob of the shut-off valve clockwise to cut off the water supply to the toilet. Flush the toilet to drain most of the water from the tank.
Inspect the interior of the toilet tank and locate the chain. Determine if the chain is broken or if it has just become detached from the flush lever or the flapper.
Remove the chain from the flapper and/or the flush lever with a pair of needle-nose pliers if it is broken. If the chain has a push clip that connects it to the flush arm, no pliers are needed. If the chain has simply become disconnected, reconnect the chain to either the flush lever or the flapper, depending on which end came loose.
Install a new chain onto the end of the flush lever if the old chain is broken. Clip it on or insert it through the hole in the end of the flush lever and pull the chain toward the end of the flush lever to secure the ball of the chain to the flush lever. Connect the other end of the chain to the top of the flapper.
Replace the toilet tank lid and turn the shut-off valve counterclockwise to restore water to the toilet.