Scientific warnings are mounting about the severe environmental consequences of wildfires, not only for biodiversity and the climate, but also for the safety of the water that millions of communities around the world rely on.
Recent studies have revealed that large-scale forest fires trigger profound changes in the hydrological system, leading to the contamination of both surface and groundwater sources. This poses a threat to human health and to ecosystems alike, according to ScienceDaily.
Impact of Wildfires on Drinking Water
In a research letter published in Science, researchers from the University of Sydney’s Centre for Water and Wastewater Technology wrote that wildfires can contaminate drinking water distribution systems, posing significant and growing public-health risks. Nearly half a billion people worldwide have been exposed to wildfires within one kilometer of their homes over the past two decades.
The researchers noted that “authorities in regions recently affected by wildfires—such as the 2025 Los Angeles fires—must ensure the safety of drinking water by monitoring and mitigating contamination within distribution systems.”
They added: “Once they enter the system, volatile organic compounds can travel through interconnected pipes, seep into water-distribution materials, and persist for months—ultimately contaminating the water delivered to consumers.”
Water Contaminants Can Cause Cancer
For his part, the letter’s lead author, Dr. Shuan Li, a research fellow in the Office of the Vice-Chancellor, said that such contaminants pose carcinogenic risks to consumers. For example, 11 months after the 2017 wildfires in Santa Rosa, Northern California, 40,000 micrograms of benzene were still detected in drinking water from distribution systems.
They added that “even short-term exposure to 26 micrograms per liter of benzene can harm children, and long-term exposure increases the risk of leukemia. These contaminants are rarely monitored in water distribution systems.”
The corresponding author, Professor Qilin Wang, also warned that climate change and urban expansion are intensifying the risk of wildfires, thereby exacerbating the threat of drinking water contamination.
He added that “levels of wildfire-related volatile organic compounds are often linked to the extent of structural damage, highlighting the growing threat that future wildfires pose to water safety, particularly in areas such as Los Angeles.”
He noted that addressing drinking-water contamination caused by wildfires requires governments to establish clear guidelines, identify wildfire-related volatile organic compounds in drinking water distribution systems, set safety limits, and implement robust monitoring and testing protocols.
