If your toilet isn't flushing completely, or not flushing at all, that doesn't mean you must call your local plumber. A quick check of your toilet's inner workings may let you locate the problem, which will likely be something you can fix for yourself. Most of the common causes, such as issues with the lift chain and flush handle, do not require a paid professional to fix or replace.
Examine the supply valve, which will be at the floor beneath your toilet or on the wall behind it, to ensure it is in the on position and sending water to the tank for flushing.
If you cannot tell which direction is on and which is off, turn the valve and flush your toilet.
If it does not flush, turn the valve to the original position before doing further repairs.
Check the lift chain or wire inside the tank. If it has come off the handle, try to replace the chain on the handle. If it is attached, ensure that it is not too short, or it will allow water to seep out. If it is too long, the handle will not be able to pull the flapper up to release the water and allow your toilet to flush.
If you have a chain system, use pliers to remove extra rings if it is too long. If it is too short, replace the chain.
If you have a wire system, loosen the screw on the handle's guide arm that will allow you to adjust the length of the wire. If it is broken, take note of where it connects to the arm and flapper before removing the old wire.
Drain your tank of water by shutting off the supply line and placing a container beneath the tank to catch water run-off. Sponge up any remaining water in the tank.
Unscrew the nut beneath the tank that connects to your supply line where it enters the tank with an adjustable wrench or pliers.
Unscrew the nut that holds the refill valve in the tank, and lift the refill valve from the tank, removing any clips or chains connected to it.
Clean the opening in the tank where the refill valve unit was before placing your new valve in place with the cone-shaped washer centred over the hole.
Tighten the locknut beneath the tank, but do not overtighten, because your tank may crack.
Connect the refill tube to the overflow pipe, likely through a new angle adaptor that will clip to the side of the overflow pipe. Connecting the refill tube directly to the overflow pipe can create a continuous siphoning of water, but you may connect the refill tube to the overflow pipe if necessary.
Reattach the supply line with an adjustable wrench or pliers. To adjust the water level in your tank, check the manufacturer's instructions, as this can differ depending on the type of refill valve.
Take note of where and how your old chain is connected before removing it to replace it with a new one.
Wearing gloves as an added precaution while working with a toilet.