A new study led by Flinders University has found that the speed at which water flows from a tap can significantly impact the possible risk of infections spreading in hospital and aged-care settings.
Production of bioaerosols - or airborne water particles that may contain bacteria or viruses - pose a significant public health concern, environmental health experts warn.
"This research highlights an often-overlooked factor in infection control, raising the potential for more infection control in healthcare settings and public spaces," says Flinders adjunct academic Dr Claire Hayward, who is now a postdoctoral researcher working on antimicrobial resistance in the community.
"In hospitals and aged-care facilities, bioaerosols generated from handwashing basins have been linked to healthcare-associated infection outbreaks," says Dr Hayward, lead author of a new article in the Building and Environment journal.
"However, there has been limited research on how basin design parameters, such as flow rate restrictors, impact bioaerosol production and transmission routes."
The findings in the latest study showed that all three flow restrictors tested produced respirable-sized bioaerosols.
While there was no significant difference in the number of aerosols and droplets originating from the source water across different flow rates, lower flow rates led to an increased generation of aerosols from the drain and greater retrograde contamination from the drain to the faucet.
This suggests that while reducing water flow may help with water conservation, it could inadvertently increase the spread of potentially harmful microbes.
Senior author in the study, Flinders University Professor Harriet Whiley, says: "These results highlight the complex relationship between plumbing design and infection control."
"By optimising design elements like aerators and flow rates, we may be able to reduce infection risks, but further research is needed to identify the safest and most effective configurations."
"The study underscores the importance of collaboration between product designers, engineers, and microbiologists to develop hand basin designs that balance functionality with infection prevention," says Professor Whiley, from the College of Science and Engineering at Flinders.
As bioaerosol transmission continues to be a concern in high-risk environments, these insights could inform future plumbing innovations and healthcare policies, researchers conclude.
The article, 'The impact of water flow rates on bioaerosol production from handwashing basins' (2025) by Claire Hayward, Kirstin E Ross, Melissa H Brown and Harriet Whiley has been published in Building and Environment, 271, art. no. 112624. DOI: 10.1016/j.buildenv.2025.112624.
Acknowledgements: This study was supported by the Flinders Foundation (Health Seed Grant 2021).
