The government said it was investigating drainage pipes in the building in Tsing Yi district in the New Territories amid worries the virus may have been spread through the system as the city goes on high alert to contain an outbreak.
Parts of Hong Kong, including restaurants, shopping malls and cafes, are almost deserted as people work from home and schools remain closed, invoking memories of 2003 when Severe Acute Respiratory Syndrome (SARS) sent panic across the city.
Hong Kong leader Carrie Lam on Tuesday appealed for residents to stay indoors as much as possible.