Since when?????
This is the first I have ever heard this!!!!!
You boil water to make it safe!!!
http://www.nytimes.com/2008/01/29/health/29real.html
http://grist.org/living/is-it-safe-to-cook-with-hot-tap-water/
https://www.cdc.gov/nceh/lead/tips/water.htm
http://www.greenbuildingadvisor.com/blogs/dept/qa-spotlight/how-safe-pex-tubing