A team of researchers and water quality and treatment experts from the University of Technology Sydney (UTS) have highlighted the potential impact of bushfires on the quality of potable water post treatment.
In a research letter published in the journal, Science, researchers from the UTS Centre for Technology in Water and Wastewater said that bushfires can contaminate drinking water distribution systems, posing substantial and escalating public health risks.
Over the last two decades, almost half a billion people globally have experienced wildfires within 1km of their home.
In the letter, the UTS researchers said, “Authorities in areas of recent wildfires, such as the 2025 Los Angeles fires, should ensure that drinking water is safe by monitoring and mitigating contamination in water distribution systems.
“Distribution systems transport drinking water from treatment plants to consumers. Water must meet safety standards before leaving a treatment plant, but contamination can occur during transport.
“Over the past decade, more than 50 volatile organic compounds (VOCs), including carcinogens such as benzene, have been detected in water distribution systems after wildfires.
“These VOCs likely enter the distribution systems through plastic pipes that have suffered thermal degradation or the infiltration of smoke into depressurised pipes.
“Once inside, VOCs can spread through connected pipes, infiltrate water distribution materials and persist for months, contaminating water supplied to consumers.”
The letter’s first author, Chancellor’s Research Fellow, Dr Xuan Li, said such contaminants posed carcinogenic risks to consumers.
“For example, 11 months after the 2017 Santa Rosa wildfire in northern California, 40,000µg/L of benzene remained in drinking water from distribution systems.
“Even short-term exposure to 26µg/L of benzene harms children, and long-term exposure increases leukemia risk.
“These contaminants are rarely monitored in water distribution systems, particularly at the consumer end, and communities often remain unaware of these risks.”
The letter’s corresponding author, Prof Qilin Wang, also warned that climate change and urbanisation are intensifying bushfire and wildfire risks, exacerbating the threat of drinking water system contamination.
“Wildfire-related VOC levels often correlate with the scale of building destruction, underscoring the growing threat that future wildfires pose to water safety, especially in areas such as Los Angeles.
“To address wildfire-driven drinking water contamination, governments must establish clear guidelines, identify wildfire-related VOCs in drinking water distribution systems, set safety limits and enforce robust monitoring and testing protocols.”
The research letter ‘Wildfires jeopardize drinking water safety’ by Xuan Li, Qizi Fu and Qilin Wang is published in Vol 388, Issue 6743 of the journal Science
