We have well water and even though I always use purified water, not the well water, in my Neti-Pot, I still boil it and put a drop of Betadine in it along with the saline powder. I don’t know if city water is safe un-boiled or not since we have never had it. Personally, I would boil all water used in a Neti-Pot. I normally only have to use mine in Spring when pollen is really bad. It helps keep my allergies from causing issues with my asthma. 🙄