would it be better to use distilled water with my five week old son, then boiled well water for his formula
In my opinion, you should use dewater for mixing your babies formula. Sometimes the well water is contaminated with substances that cannot be easily eliminated by boiling water. Use the distilled water instead just to be safe.
Never use distilled water. Over drinking can cause osmotic effect in which salts leave the cells and shock/death etc..Google it if you dont believe me.