Singapore's 4.4 million people live within a city-state occupying only around 700 square kilomteres. Most of the freshwater used to be transported to the country from Johor in neighbouring Malaysia via three large pipelines stretching across the 2 kilometre causeway that separates the two states. This was a necessary measure as, despite an annual rainfall of 2,400 milimetres per year, Singapore has no large water catchments external to the city or groundwater aquifers from which to draw water to meet its needs and is considered a water-scarce country. In May, countries will meet in Nairobi for UNEA 2 – the world's de facto "Parliament for the Environment" – to discuss how the United Nations Environment Programme can deliver on the environmental dimension of the 2030 Agenda for Sustainable Development. Decoupling water use from economic growth is one of the ways to ensure the availability and sustainable management of water and sanitation for all –a key goal of the 2030 Agenda. Singapore's example is striking. To overcome this major obstacle in the country's development, Singapore's water utility, the Public Utilities Board (PUB) invested in measures to reduce demand for water by improving efficiency, cutting waste and expanding alternative sources of supply. This resulted in significant levels of decoupling of water use from economic growth. Over the last 40 years, Singapore's economy has grown by a factor of 25. It has managed one of the fastest transitions from a 'developing' to a 'leading first-world' country in history, with one of the highest per capita incomes in Asia. In the same period, its population has grown by a factor of 2.5, from 1.7 million to 4.4 million today, yet water use has only increased five-fold. In terms of water consumption in absolute terms this represents a five-fold relative decoupling for the whole Singapore economy. This has been achieved through effective, purposeful and long-term demand management, water efficiency and water-leakage prevention programmes. Per capita residential water use has fallen consistently for the last 15 years providing an exception to a worldwide increase. This result is no accident. The Singapore government is one of the few with a publically stated target for residential sector per capita water use of 140 litres per person per day by 2030. Singapore and its Public Utilities Board have also reduced growth in water consumption by minimizing water leakage throughout the city's water infrastructure which is tracked by measuring the level of 'unaccounted for water'. This has been reduced from 9.5 per cent of total water production in 1990 to 5 per cent by 2002. This is a level that no other country can match at present and contrasts with the fact that unaccounted for water in most Asian urban centres now ranges between 40 and 60 per cent. Singapore has also reduced absolute freshwater consumption by 60 per cent through the development of alternative sources such as extensive stormwater harvesting, treatment and reuse, treated and recycled municipal water, and desalination. Today, 35 per cent of Singapore's water comes from rainfall captured on its own limited territory, about 15 per cent is high-quality recycled water produced from wastewater by its 'NEWater' treatment plants, 10 per cent comes from desalinated water, and only around 40 per cent is imported from Malaysia. In 2010, the Singapore government and its Public Utilities Board announced that they have committed to replacing the final 40 per cent of imported freshwater usage with further water efficiency improvements as well as the development of greater levels of water recycling and desalination so as to eliminate the need for imports from Malaysia by 2060. This remarkably integrated and holistic approach to sustainable urban water management was made easier by the fact that Singapore's Public Utilities Board currently manages the entire water cycle of Singapore, as well as electricity and gas. This includes sewerage, protection and expansion of water sources, stormwater management, desalination, demand management, pricing, community-driven programmes, catchment management, and public education and awareness programmes, leading to wastewater treatment and reuse on an unprecedented scale.
In May, hundreds of key decision makers, businesses and representatives of intergovernmental organizations and civil society will gather in Nairobi for UNEA-2 at the United Nations Environment Programme headquarters in Nairobi. The assembly will be one of the first major meetings since the adoption of the 2030 Agenda for Sustainable Development and the Paris Climate Agreement. The resolutions passed at UNEA-2 will set the stage for early action on implementing the 2030 Agenda, and drive the world towards a better, more just future.