This is not an unlikely scenario. It is one the insurance companies are well accustomed to. For this reason we advise our customers to shut off the water supply to their homes before going on vacation. It is very important, however, to verify that you indeed turned off the water. We had a client “turn off” their water only to receive a phone call while on vacation that a pipe burst, flooding their apartment and causing damage to the neighbors down below as well.
So before you leave on vacation turn off the water outside at the water meter. Relieve the pressure in the system and verify that it really is off by opening a tap in the apartment. This way you will know if you turned off the wrong water supply or if the valve is perhaps faulty and not closing completely.