The City of Edmonton has been suffering from sewer odour problem for many years. Ten years of odour complaints data from 2008 to 2017 were statistically analyzed to identify major factors that relate to the odour problem. Spatial and temporal distributions of odour complaints in the city were first presented. Then relationships between the complaints and physical attributes of the sewer systems were analyzed by introducing a parameter of risk index. It was found that the snowmelt and storm events could possibly reduce odour complaints. Old sewer pipes and large drop structures are statistically more linked and thus significantly contribute to the complaints. The risk index relationship for three pipe materials is clay pipe > concrete pipe > PVC pipe. Combined sewers are more problematic in terms of odour complaints than sanitary sewers. And no clear correlation has been found between the changes of sewer pipe slope or angle and the complaints.