For Henry Hung Chi-kuen, a veteran of the plumbing and drainage industry with more than 60 years of experience, toilets are not only how he earns his living but also something of an obsession.

“Wherever I go [around the world], the first place I go [to] is the public toilet,” he said enthusiastically.

The 78-year-old also buys toilet-themed souvenirs from different countries, proudly displaying them behind his desk.

Often referred to as “Dr Toilet”, Hung is a founding member and president of a non-profit charitable organisation that advocates for a clean, accessible and safe toilet environment.

The Hong Kong Toilet Association is best known for its annual survey ranking the city’s best and worst public loos. This week, it named the one in the nightlife district of Lan Kwai Fong as the city’s cleanest, despite its high turnover.

Hung said his more than 60-year career had fuelled his passion for toilets, but it was the city’s outbreak of severe acute respiratory syndrome (Sars) in 2003 that prompted him to do more for the sake of people’s health and well-being.