Dangerous levels of legionnaires' disease were found in more than three per cent of the buildings inspected in the last eight months, according to government data.
Traces of the potentially deadly Legionella pneumophila bacteria, which cause the disease, were recently found in the new HK$5.5 billion government headquarters at Tamar days after education chief Michael Suen Ming-yeung was diagnosed with the illness.
The bacteria was found in four samples taken from a tap in Suen's private bathroom at Tamar.
Health department officials collected another 31 water samples from the complex yesterday, including three from the chief executive's office. The results are expected in a few days.
Fifteen of the 464 buildings inspected citywide in the last eight months uncovered traces of the disease above the safe level of 1,000 bacteria per millilitre, data from the Electrical and Mechanical Services Department shows.
The affected buildings are in areas including Kwun Tong, Causeway Bay, Sai Kung, Wong Tai Sin and Tuen Mun. Six of the buildings in Kwun Tong are old and due for demolition.