[2020] Nearly all my quests are at the waterworks POI...

As I recall the waterworks is a tier IV building. Whatever your max quest tier is, all traders will heavily favor that tier. The general consensus is that they should rejigger this to offer more lower tier quests. For me on tier V, it’s meant alternating Shamway Factory, Shotgun Messiah, Shamway Factory, Shotgun Messiah. So at least your waterworks fatigue will be temporary, before tier V fatigue sets in.