The S$3.65 billion Deep Tunnel Sewerage System (DTSS) is an efficient and cost-efficient solution to meet Singapore’s long-term needs for used water collection, treatment, reclamation and disposal. Conceptualised and managed by PUB, it was conceived as a cost-effective and sustainable solution to meet Singapore’s long-term used water needs.

The mammoth DTSS (Phase 1 & 2) project consists of two large, deep tunnels crisscrossing the island, two centralised water reclamation plants, deep sea outfall pipes and a link sewer network.

The project consists of two large tunnels with a total length of 80 km and 170 km of smaller link sewers. The large tunnels are 50 meters below the surface and have diameters up to 6.5 m. The tunnels carry the sewerage to two new centralized water reclamation plants. Treated effluent is then discharged into the Straits of Singapore via deep sea pipelines.