Singapore

City Water System

Singapore manages the complete urban water cycle through PUB, combining national planning, utility operations, regulation, drainage and coastal-protection responsibilities. The Four National Taps—local catchment water, imported water, NEWater and desalinated water—are managed as one portfolio rather than as independent sources. Universal urban service and a tightly controlled distribution system provide a strong operating base, while land scarcity, industrial growth and the 2061 water-agreement horizon keep long-term supply independence central to investment decisions.

Resources, Supply & Demand

Current national demand is approximately 440 million gallons per day and is projected in the report to reach about 880 mgd by 2065. NEWater and desalination currently provide weather-resilient capacity, while the stated target is for weather-resilient sources to meet 85% of demand by 2060. Industrial demand is expected to become the dominant component of consumption. Pricing, efficiency requirements, mandatory recycling for selected industries and household conservation therefore operate as supply-security instruments alongside new physical capacity.

Wastewater & Circular Infrastructure

Singapore’s used-water system is part of its supply architecture. The Deep Tunnel Sewerage System conveys flows to large treatment and reclamation facilities, enabling NEWater production and supporting industrial supply. DTSS Phase 2 and Tuas Nexus integrate conveyance, treatment, water reclamation, energy recovery and waste management. This circular model reduces reliance on rainfall-dependent resources, but its performance depends on coordinated flows, treatment efficiency, industrial demand and continued operational capability rather than infrastructure capacity alone.

Climate Adaptation & Investment

PUB’s resilience mandate spans drought, intense rainfall, drainage, coastal defence and low-lying asset exposure. Supply diversification reduces rainfall dependence, while major drainage and coastal initiatives address flood and sea-level risk. The proposed Long Island project illustrates the integrated approach by combining coastal protection, land formation and a potential new freshwater reservoir. The principal delivery challenge is coordinating long-horizon adaptation with energy-efficient treatment, rising industrial demand and the transition toward greater domestic supply security.

Key Challenges

1. Meeting rising industrial demand without weakening municipal water security.
2. Expanding weather-resilient supply while containing the energy and emissions intensity of treatment.
3. Coordinating wastewater reclamation, industrial recycling and NEWater feedstock requirements.
4. Delivering drainage and coastal protection for increasingly intense rainfall and sea-level exposure.

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