New research from Flinders University reveals a hidden risk in healthcare handwashing: water-saving taps designed to conserve resources may inadvertently amplify germ transmission through airborne “splash back.” The study, published in Building and Environment, found that slower water flow rates in hospital and aged care basins increase bioaerosols—airborne particles carrying bacteria or viruses—from drains, raising infection risks.
Lead researcher Dr Claire Hayward, a Flinders University adjunct academic, warned that basin design flaws are a critical blind spot in infection control. “In hospitals and aged-care facilities, bioaerosols generated from handwashing basins have been linked to healthcare-associated infection outbreaks,” she said.
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.
The study tested three flow restrictors, commonly used to reduce water consumption, and found all produced respirable-sized bioaerosols. While water conservation efforts are vital, senior author Professor Harriet Whiley stressed the need for balance: “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 findings urge collaboration between engineers, designers and microbiologists to rethink hand basin designs “that balance functionality with infection prevention,” said Whiley. With bioaerosol transmission remaining a concern in high-risk settings, the study calls for updated healthcare policies and plumbing innovations to mitigate unintended consequences.
Ritchelle is a Content Producer for Healthcare Channel, Australia’s premier resource of information for healthcare.
