Cold Water Coming from Hot Water Faucet 

We moved into a new home last week and recently noticed that the guest bath cold water faucet is dispensing warm water. All other cold water faucets are supplying cold water.

There are two issues which could be the source of the problem. The water supply line could be crossed somewhere which would create warm water coming from the cold water faucet. If that were the case, more than likely the hot water faucet would be dispensing cold water. More than likely the cold water line is touching the hot water line, somewhere within the plumbing grid line and this is creating a small warm up of the cold water. If this is a newly constructed home, and it sounds as if you are within the first two years of home ownership, this issue is under warranty and your contractor has responsibility under performance standards to take corrective action.