Sinkhole and ground surface collapse frequently occur in urban areas such as highway, roads or around buildings. Usually the failure process in rather sudden without much evidence or obvious signs. This catches people by surprise and results in accidents, injuries or even death in some cases. From current studies and case analysis, most of the sinkholes in urban area are attributed to leaking of water supply lines or sewer pipes. The mechanism is summarized as the soil loss around defective sewer pipes, and this erosion void further evolved to the ground collapse or sinkhole.