With the influence of science, the way people addressed challenges in the past has now changed. It's easier to make "stuff" smart now-to-day with the advancement of IoT. Thus, with the advancement of smart infrastructure and the emergence of the Internet of Things (IoT), it is possible to calculate real-time flood prediction in Bangladesh's sewerage system and also to track the ecosystem of underground tunnels easily and efficiently. This study represents the development of a sewerage system for an existing sewerage system in Bangladesh that can predict sewerage system overflow and implement a hazard condition monitoring system prototype using IoT technology by calculating risk factors such as calculating the amount of toxic gases in underground tunnels. We should save the lives of the employees who work in caves, contact workplaces and manhole underground work.