People with experience working in and around municipal water infrastructure: Do you drink tap water? Are there times when you do not?

This question is obviously intended for those that live in places where tap water is "safe to drink."

I live in Southern California, where I'm at the end of a long chain of cities. Occasionally, the tap smells of sulfur, hardness changes, or it tastes... odd. I'm curious about the perspective of people that are directly involved and their reasoning.