If you know you have chlorine or chloramines in your water you do want to use 1/4 Campden tablet per 5 gallons of water (or use a pinch of potassium metabisulphite). Stir well. Just boiling alone will not drive off chloramines in reasonable time.
Not treating for Chlorine or Chloramines can ruin your beer. It leaves a medicinal, plasticky, band-aid like flavor. The flavor threshold is pretty low, and easy to detect. Could you mistake this for sourness?
Well, now you experienced that double posting also leaves bad flavors