A toilet that does not flush correctly can very easily be corrected if you know what to look for. If you looking inside your toilet tank you will see a chain that is attached to the flush handle. At the end of this chain is the flapper. It’s a rubber flap that makes a water proof seal over the valve. If the flapper is bowed, or in in good condition, or if the valve has any debris or corrosion the flapper will not seal correctly, causing the toilet not to flush correctly. As you can see here, this is a very simple repair to do.