However, a considerable proportion of wastewater is not treated before being discharged or reused. Japan is the second largest producer of wastewater with 16.9 billion m3 generated in 2011, and 11.6 billion m3, or 69 per cent of the total treated. Singapore is the only country in Asia and the Pacific where all wastewater is treated, or 0.5 billion m3 in 2013. (