Internet of Things (IoT) is revolutionizing all spheres of our lives leading the way for us to evolve into smarter societies. Wireless sensor networks (WSNs) are an integral part of the IoT ecosystems. Reliability, resilience, and energy conservation are the three most critical WSN requirements. Fault tolerance ensures the reliability and the resilience of WSNs in case of failures. This paper proposes a hierarchical clustered dynamic source routing (HCDSR) technique to improve fault tolerance and energy-efficient routing for WSNs. A survey of fault tolerant and energy-efficient routing techniques for WSNs is given. A taxonomy of fault tolerant techniques is introduced. The proposed HCDSR is simulated and compared with LEACH (low energy adaptive clustering hierarchy) and DFTR (dynamic fault tolerant routing) protocols to evaluate its performance. The results show that HCDSR outperforms LEACH and DFTR in terms of the total network energy, the number of nodes alive after a given time, and the network throughput. Directions for future work are given.