Improperly functioning plumbing may be one of the more frustrating problems a homeowner has to deal with. If the malfunctioning toilet is also your only toilet, handling the problem right away is imperative. Before you call a plumber because your toilet won't flush, check to see if the problem is a simple one that you can fix yourself. Some of possible causes of a toilet that won't flush are shutoffs in water supply, clogs or faulty parts inside the tank.
Check the valve at the back of the toilet. If the toilet will not flush, the water may be shut off. Turn the water supply back on by using the valve.
Determine whether the toilet is clogged. Fill a bucket with a minimum of a gallon of water. Lift the toilet seat and pour the water very quickly into the toilet bowl. If the water does not flush and drains slowly, you likely have a clog. Use a toilet plunger or auger to break up the clog.
Examine the holes on the inside of the toilet bowl under the rim. According to Ask the Builder expert Tim Carter, if you do not have a clog in the drain, these holes may be clogged with mineral deposits. Use a straightened wire coat hanger to clean these out. Then do the same to the siphon hole, which is located at the exit hole of the toilet bowl.
Remove the toilet tank lid and examine the inner mechanisms to determine if they are working properly. With the lid off, try flushing the toilet again. (Do not flush if your toilet threatening to overflow.) Check to see if the handle mechanism is stuck, or if the lift chain is too short. You may need to replace them.
Call a plumber if you are unable to determine the cause of the problem. You may have a larger problem that requires professional help. You may have a clog in the main drain line, a cracked pipe or a septic tank that needs to be drained.