Recently, two residents living on different floors of a high-rise tower called Hong Mei House, in north-western Hong Kong’s Tsing Yi, were found to have been infected with coronavirus and this incidence has given rise to fear that the coronavirus might have been transmitted via the building’s pipes. The officials’ fear is not without reason as the two infected people lived in two different apartments, 10 floors apart, in the same building. This incidence could have far reaching implications in most of the Asian Mega cities which are densely populated and multi-residence buildings are common in these cities.
Typically, bathroom drains have a U-shaped trap that prevents fluids and odour from coming back up. However, the air would flow backward through the drains under certain circumstances. For example, when the bathroom is in use, with the door closed and the exhaust fan switched on, there could be negative pressure to extract contaminated droplets into the bathroom. Contaminated droplets could then get deposited on various surfaces such as floor mats, towels, toiletries and other bathroom equipment. Tests have also found the virus present in patients’ stool, suggesting the virus may be able to spread through faecal contamination. And the virus can cause abdominal symptoms, including diarrhoea and nausea. However, it should be noted that even if coronaviruses can spread through pipes, it’s not a common mode of transmission.
In 2003, during the outbreak of severe acute respiratory syndrome, or SARS (which is also caused by a coronavirus) officials found that the virus was likely transmitted in a Hong Kong apartment tower through faulty plumbing, according to the World Health Organization.
The pipes that carry raw sewage should be kept separate from people. Further, if there are leaks or breaches in the pipes, it could allow people to be exposed. A faulty piping system could allow the virus to become “aerosolized” out of a pipe and get into the surrounding air.