@heidisolonely Okay, so the thing is...it's not about water contamination, but requiring the water to be a certain temp in order to kill any bacteria in the powdered formula because it's not sterile.
Where I am, Canada ...we were told to boil for 2-5 minutes. No less. There were no instructions on when to add the water. But, after reading, mixing the boiled water immediately can possibly kill the nutrients in the formula, that's why they say to cool it some first. That logic does not work when some places say to cool to room temp lol
For the first few months, we typically followed the, boil and cool for no more than 30 minutes rule. We would then make up a pitcher and put it in the fridge and use within 24 hours.
Now...he's almost 6 months and I just use warm tap water.