I bought a new house for a week. Before I move in I notice that my driveway have sunken. The deepest point is 1/2 inches deep and the area that sunk is the left half of the driveway. The right half is OK. The reason that the left half is because rain water found it way to the bottom of the left half of the driveway. My questions is whether the builder is responsible to replace the sunken part of the driveway as I have 18 months warranty on the house. My friend said that the driveway will get worse in the next winter.