Is a timing belt replacement required when a water pump is replaced?

Its not required but it a good idea and while your there i always change the tensioner pulley too, Your going to kick yourself if your going to maine on vacation and the pump starts leaking or tensioner bearing goes.

It's not required, but I would highly recommend that you do so.It will save you more problems down the road.

I agree with both answers, your paying a lot in labor and you would get a better warranty if you do timing belt , water pump and all pulleys. There are oil seals there to, oil can make belt go bad. If leaking i would replace.