HK Magazine Archive

What Does Hong Kong Do Better Than Any Other City?

PUBLISHED : Wednesday, 15 July, 2015, 2:14pm
UPDATED : Wednesday, 19 October, 2016, 4:45pm

Dear Mr. Know-It-All,
They say Hong Kong is a world-class city, but does it do anything better than all the other major metropolises? – Record Man

Hong Kong is a global pioneer in one unlikely area: how we flush our toilets. 

Despite the seemingly endless rain, Hong Kong has never been self-sufficient when it comes to water. Our huge population, tiny landmass and loads of uncooperative bedrock mean that we only gather 20-30 percent of our needs from rainfall and local water sources. The rest is imported from the Dongjiang River in Guangdong, about 80km away. The process costs about $4 billion per year.

Until the 60s water rationing was a very real issue in Hong Kong. The June 1963-May 1964 drought crippled the city, with only four hours of water supply available every four days. The Hong Kong government set out to resolve the issue with a three-pronged approach: building more reservoirs, importing water from China—and using seawater to flush our toilets.

While the seawater scheme was piloted in the late 1950s, it only reached a critical mass in the late 60s, and the last water rationing in Hong Kong took place as late as 1982. It’s still being rolled out, with salt water flushing hitting Pokfulam in March 2013 and Wah Fu Estate in October 2013, and the Northwestern New Territories in March this year. Now about 85 percent of the SAR’s population uses seawater for flushing—it comes out to about 748,000 cubic meters of sea water each day, water that would otherwise have to be bought in from China at 2.5 times the price. The 1,698 kilometers of salt- and freshwater pipes running through our city makes it the most extensive dual-water system on the planet.

But the piping isn’t what’s impressive. Of the many coastal cities in the world, Hong Kong is actually the only major metropolis to use sea water for flushing. There are only a few other locales that use a similar system: the island town of Avalon, California, plus a handful of the world’s most isolated islands.

It comes at a cost, of course—for one, corrosive seawater means pipes degrade faster, although the price of replacing them is still cheaper than importing water. For another, Hong Kong’s easy access to water—our water rates are some of the cheapest in the world, and we don’t pay for seawater at all—means that the city actually has one of the highest, most wasteful levels of water consumption per capita on the planet. 

Worth thinking about when you leave the tap running as you brush your teeth. Oh, and if you have a dog: Don’t let him drink from the toilet.