As an island state, Singapore obtains a significant portion of its water supply from state-of-the-art rainwater and used water treatment. Back in the 1990s, Singapore’s National Water Agency, PUB launched a massive project to strengthen the nation’s water security and when completed, the Deep Tunnel Sewerage System (DTSS) will include a total of approximately 200km of newly built sewers running up to 60m deep underground. It is designed to meet Singapore’s long-term needs for used water collection, treatment, and reclamation.