When it comes to water supply, Hong Kong has been lucky. But we shouldn’t count on our fortune going into the future. A two-part study, the second of which has just been released by the think tank Civic Exchange, is a timely reminder of the challenges ahead. The study calls for diversifying the city’s water supplies, of which up to 80 per cent currently comes from the Dongjiang, or East River. No doubt it is necessary, but easier said than done. The study casts the main issues in terms of environmental sustainability. But the real threat, I think, is increasing competition between major cities in the Pearl River Delta over water use in the coming decades, especially those within the Greater Bay Area. After all, we are talking about 70 million people and rising who are competing for the same finite and often polluted water sources. Up till now, Hong Kong people fret mostly about the water quality and value for money of our over-reliance on Dongjiang supplies. But as the city loses Beijing’s favouritism, other under-sourced cities will stake their rightful claims to better water quality and greater quantities. Think tank urges Hong Kong to reconsider water import deal with mainland China Most Hong Kong people take for granted the generally higher quality of water and foodstuffs supplied to Hong Kong from the mainland. This favouritism is unlikely to continue. In the past two decades, delta cities, including Hong Kong, have fought for higher upstream catchments in the Dongjiang to get fresher water. Indeed, there are inherent inequities as cities in the upper stream have been told to forego development to maintain water quality while those in the mid- and lower stream have powered ahead with their economic development, along with higher pollution. Civic Exchange recommends greater local water catchment, recycling of reclaimed water, better cooperation between local water and drainage officials as well as planning desalination as a possible option. These are good technical and localised options. Here’s an unpopular but powerful option: raise water charges to the real cost. But Hong Kong will not wean itself off Dongjiang supplies any time soon. As has been argued by local geographer Lee Yok-shiu and others, the major cities in the delta region need to coordinate their policies on water supplies and sustainability. Otherwise, they will fight each other more openly in the years ahead. And Hong Kong is likely to be left out in the cold as it loses its status as Beijing’s favoured child.