It is known that sewer problems are the major causes of road cave-in. The objective of this study is to analyze the risk of road cave-in due to storm sewer laterals. We investigated 174 storm sewer laterals using a zoom camera at O-dong area in Seoul. The causes of road cave-in were classified into five cases: breakage of rigid pipe, deformation of flexible pipe, out of pipeline alignment, changing pipe material or changing pipe diameter, and a poor linkage between lateral and sewer. In addition, all defects were sorted into five grades based on the severity rating at storm sewer laterals. In this study, the most fragile pipe materials were found to be concrete pipe and polyethylene pipe, which recorded 2.3 and 1.69 defect rates. With regard to the causes of road cave-in, deformation of flexible pipe has a large influence on road cave-in at present. On a long-term basis, the two causes, out of pipeline alignment and a poor linkage between lateral and sewer, could have more influence on road cave-in.