Cast iron (CI) pipes are used in a significant proportion of US water distribution systems. Due to the number of old and deteriorated elements still in operation, the failure rates of CI pipes in most water utilities are higher compared with other materials. This study assessed the business risk exposure (BRE) for each CI water main in three selected service areas in California, taking into account both the likelihood of failure (LOF) and consequence of failure (COF). Spatiotemporal-based emerging hot spot analysis was used to examine LOF and unique critical facilities were considered for COF. The resulting BRE-based heat maps can be a helpful tool in enabling water utility executives to make more informed decisions and in mitigating the risks associated with the deteriorating CI pipe networks.