Fact 4: The green house is on the left of the white house.

This means the green and white houses are next to each other with the green on the left. As I'm writing this, I'm realizing that this is open to interpretation though -- maybe it just means that if you look at the five houses, the green one is to the left of the white one. But I can defend my choice with a quick piece of logic: my choice leads to only one solution. If my interpretation of the words is incorrect, my choice is still consistent with the more general interpretation. If the more general interpretation has only one solution, it must be mine. If the more general interpretation allows for more than one solution, then the problem would be indeterminate; since the problem implicitly claims to have a unique solution, this would be inconsistent. Thus I like my choice of interpretation.

Fact 5: The green house owner drinks coffee.

Together these two facts mean we have to fit a piece that looks like: