It's actually due to the history of indoor plumbing that depicts the placement rather than codes and regulations!
When indoor plumbing was first introduced, it was cold water only and normally by hand pump. Since the majority of people are right handed, the pump was placed to the right of the basin.
As time progressed, hot water taps were introduced. Since cold was already on the right, and more commonly used, the hot water tap was placed on the left.
Now, if the majority of the household was lefties, this would have been the opposite, but for the majority, this practice was passed down through the generations as a standard of having hot on the left.