Sorry this may be stupid/obvious but I've bf and am blissfully ignorant about formula rules.
DS is going to nursery (boohiss) and will need a feed in the aft, they've asked me to bring the measured water and formula. I've only mixed it from freshly boiled water, right prior to feeding, which is annoying as takes ages to cool etc. I've been giving him tap water for months though...so am I faffing for nothing?