Bring water and sugar to a boil over medium-high heat, stirring to dissolve sugar.
Stir the cranberries into the boiling water. As the water returns to a boil, turn the heat down to medium. Allow the cranberries to simmer until the skins start to pop and the sauce begins to thicken, about 7 to 10 minutes, stirring occasionally.
Turn off the heat. There's no need to remove the sauce from the stovetop unless you need the space. Either serve it warm or refrigerate your sauce once it has cooled to room temperature.
Serve cranberry sauce either cold or at room temperature.