No hot water coming from tap on the back half of the house as well as upstairs. The cold water works fine. The house is only a year old. What in the world could this be?

Hi TT...

Could be that a shutoff has become clogged... or maybe you have a recirculating hot water line that has a defective circulator..?

Here, you need to start at a point that you know you get hot water and then chase the pipe out to the next spot in the line to a point where you don't get hot water. Check for any shutoffs, circulators, etc. that are between and see what you can determine from there...

Let us know what you find...

MARK