Bottled water, and the advertising claims made on its behalf, must constitute one of the longest running corporate jokes inflicted on contemporary consumers. From the French Alps, to Fiji, Hawaii, the Spanish Pyrenees and beyond - anywhere exotic-sounding enough will do to inspire a successful advertising campaign.

And with what end result? In terms of taste and chemical composition, a product identical to that obtained from a street-side standpipe in Kennedy Town flies off the supermarket shelves; tills ring up profit margins that even Hong Kong's property cartel would consider excessive; plastic bottles mount up in landfills; and within the hour, expensively imported H2O becomes freely distributed local urine.

A common misconception - aided and abetted by the soft-drink-bottling and water-distilling industries - is that Hong Kong's water shouldn't really be swallowed from the tap. One has only to witness the number of people who immediately react with horrified discouragement if one suggests drinking from a tap to realise just how deeply ingrained this prejudice is. In fairness, faulty pipes and ill-maintained storage tanks in high-rise buildings can cause discolouration and an unpleasant metallic taste. Water - unless it is polluted or otherwise contaminated - is tasteless; so whether from a residential tap or an imported bottle at a high-end restaurant, it should all taste the same.

Nineteenth-century Hong Kong was renowned internationally for its readily available potable water; which was why Hong Kong Island attracted British attention in the first place. Waterfall Bay, on the East Lamma Channel, was marked on Admiralty survey charts as far back as the late 1740s - nearly a century before the first Anglo-Chinese war saw Hong Kong Island's cession to Britain.

Early on, quality water gave Hong Kong a significant advantage - it was one of the few places on the China coast with water fit to drink. Its water supplies were stream- or spring-fed, and gathered from closely protected, extensively re-afforested catchment areas within which little or no human habitation was permitted. The legacy of this careful husbanding of a scarce, vital resource can still be seen today: more than 40 per cent of Hong Kong's land area is contained within country park boundaries. Most of that land area was originally designated to protect water catchments and has been generally off-limits for decades. These days the country parks provide a vital recreational resource for the city, as well as water security.

Other coastal cities, such as Shanghai and Macau, relied on river water, and this - given the extent of ground-water contamination - reinforced Hong Kong's pre-eminence. Water in other places had to be filtered and settled with alum to remove silt and other impurities. By the 1930s, Shanghai's potable supply was safe to drink from the tap, even though the city's water was drawn from a river that flowed through hundreds of miles of countryside with significant agricultural and human effluent run-off, and - near Shanghai itself - suffered high levels of industrial pollution.

Today, Hong Kong's water is mostly drawn from protected catchments on Guangdong's East River, and exceeds World Health Organisation standards at source. Nevertheless, this basic fact is one of the most underextolled achievements of Hong Kong governments past and present. Some examination of exactly how many officials have ended up working for the bottled-water trade after retirement would, no doubt, make for interesting reading.