Under British rule, Hong Kong -- including Kowloon and the New Territories -- was a wide open, freewheeling city, a bastion of pure capitalism. You could get anything you wanted, day or night and on short notice. Made a number of port calls when in the U.S. Navy, and had only one bad experience (foolishly drank the local water and paid for it.)
Back in the day when I lived in Japan and worked for Mitsubishi, one of the well traveled guys in the company gave me a sound piece of advice: On these short-term business assignments, go to your local market, buy a two liter bottle of water and drink only from that while you are away unless you are willing to drink the local alcohol or Coca-Cola products instead. They are world famous for using safe water and even sell bottled water in some countries.
That advice served me well and the only time I almost got in trouble for it was when a Saudi customs agent gave it a good looking over. He finally scowled and put it back in my luggage when I invited him to open and sniff.