My toilet is partially blocked - it drains when flushed but then some soiled water flows back at the end of the flush so that the water in the toilet is dirty.

angeloj, December 2010

Could be blocked..the old fashioned method is to put water into the toilet pan and vigorously plunge it with a mop (being careful not to push through the bottom of the loo) You can usually tell if it is blocked if the water level in the pan is higher than usual after flushing.

Pedro, December 2010

if solids are going away ok it isn't blocked there probably isn't enough water in the cistern to do a proper flush

brian, December 2010