What water to drink during fast

I went to cvs today to get distilled water but they were all out. Out of all the choices they had left I decided to get cvs brand natural spring water. I know it's not good to have chemicals or flouride when fasting, so does anyone know if spring water has any flouride. Maybe other kinds of spring water don't, but to me it seems like cvs would be the kind of company that would put it in because of how they are tied to pharmecutical companies Tweet