Mazda 3 2007: Leaking water pump

I have had to replace three water pumps in my 2007 Mazda 3 due to them leaking! To date it has been covered by warranty and hasn?t cost me anything, but I am concerned that with the warranty nearly finished that any future pumps will be replaced at my expense. I?m also afraid that because of the importance of the water pump in alloy engines that if it does fail completely while driving I would be up for major repairs! I have spoken to Mazda and the dealer about my concerns about what I think is a weak link in a good car, but they say it?s normal!