I think I would reread Maranjo’s post and NOT use tap water for anything, particularly tooth brushing, if I was staying anywhere on the French side.

That said, we’ve mostly stayed on the Dutch side of the island for over 45 years at least annually and we have always used tap water with no side effects. Don’t ask me why, but I buy two gallons of water every trip and use it exclusively for making my coffee and iced tea. But for everything else, including drinking water, tooth brushing and ice cubes, we use the tap water. Neither of us has ever had an issue on the island and having experienced a mild bout in Puerto Vallarta (ice cubes....) I can only say THANK YOU, GOD!, because it was brutal.