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The impact of wildfires in proximity to urban centers extends beyond the immediate destruction of structures and natural habitats; one significant concern is the potential contamination of potable water supplies, as highlighted by experts from the University of Technology Sydney (UTS).
A recent research letter featured in the journal Science reveals that wildfires can significantly compromise drinking water distribution networks, thereby presenting serious and increasing public health risks. The findings indicate that nearly 500 million individuals globally have lived within one kilometer of a wildfire over the last 20 years.
The researchers emphasize the need for local authorities in wildfire-affected areas—citing the 2025 fires in Los Angeles as a recent example—to ensure the safety of drinking water through diligent monitoring and remediation of contamination in water systems.
Drinking water distribution systems play a crucial role in delivering water from treatment facilities to consumers. While water is required to meet safety standards before it is released from treatment plants, the transportation phase is vulnerable to contamination.
In recent years, over 50 volatile organic compounds (VOCs), including known carcinogens like benzene, have been identified in these distribution systems following wildfire events.
These VOCs typically infiltrate the distribution systems via plastic pipes that have been thermally compromised or through the entry of smoke into depressurized piping networks. Once contaminating substances make their way inside, they can disseminate through interconnected pipes, permeate the materials used in water distribution, and linger for extended periods, resulting in tainted water reaching consumers.
Dr. Xuan Li, the first author of the letter and a Chancellor’s Research Fellow, underscored the potential cancer risks these pollutants pose to the public.
For instance, 11 months after the 2017 Santa Rosa wildfire in northern California, water samples revealed a concerning level of 40,000 micrograms per liter of benzene in the drinking water from affected distribution systems.
Short-term exposure to even 26 micrograms per liter of benzene is known to adversely affect children, with prolonged exposure heightening the risk of leukemia.
Unfortunately, these hazardous compounds are infrequently monitored within water distribution networks, particularly at the consumer endpoint, leaving communities largely unaware of this looming danger.
Professor Qilin Wang, the letter’s corresponding author, cautioned that ongoing climate change and urban development are amplifying the risks associated with wildfires, further endangering drinking water systems.
“The levels of VOCs linked to wildfires often correlate with the degree of destruction caused to buildings, highlighting an increasing threat to water safety, particularly in regions like Los Angeles,” Wang stated.
To effectively tackle the issue of drinking water contamination arising from wildfires, it is essential for governments to establish clear protocols, identify wildfire-related VOCs within water distribution systems, implement safety thresholds, and enforce comprehensive monitoring and testing practices.
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