Common problems found with toilets Although Toilets come in a wide variation in their various designs, the general operation of each toilet will always remain the same.  Common problems found with toilets can easily be identified firstly by understanding the operational sequence of a toilet.   The inner mechanism of a toilet cistern works on three basic principles, the mechanics of the inlet valve, syphon and the incoming water supply.  A combination of the three is required to trigger a toi...