Two years after the Camp Fire decimated the idillic town of Paradise in Butte County, California, we reflect on the short- and long-term impact of wildfires on drinking water quality.

More than 8000 wildfires have devastated over 4 million acres across California this fire season — setting a new state record. Wildfires are not only occurring more frequently and burning more intensely, they are also increasingly sweeping through residential areas across the western states. This not only places these residents at immediate risk due to the dangers posed by fire and smoke inhalation, but can also pose a long-term health risk if their local water supply becomes contaminated with toxic pollutants.

"Most people are not aware that when there are major wildfires, there is often some pretty serious water contamination," says Erik Olson, NRDC's senior strategic director for public health issues.

According to a recent study that appeared in the scientific journal AWWA Water Science, toxic compounds such as benzene and other VOCs were detected in water distribution systems supplying areas affected by the Tubbs wildfire in 2017 and the Camp Fire in 2018.

The Camp Fire, which burned through the town of Paradise in Butte County, California, decimated more than 18,800 structures including thousands of homes, and was responsible for the loss of 86 lives. In the aftermath of this devastating fire, water samples obtained from the Paradise Irrigation District contained benzene at 2,217 parts per billion (ppb). The federal drinking water standard for this carcinogenic compound is a mere 5 ppb, and in California, the legal safety limit is lower still, at just 1 ppb.

Other toxic VOCs including toluene, styrene and naphthalene were also detected at levels which exceeded drinking water safety standards, posing a health risk to residents. Depending on the levels of exposure, these health risks range from mild conditions such as nausea and skin irritations to more serious health effects that can affect the immune, reproductive and nervous systems and cause developmental problems in children. Exposure to these toxic chemicals over the long-term can cause cancer.

Considering that 80% of US freshwater supplies originate from forested lands/watersheds, it is vital that a concerted effort is made to protect water quality both during and after a wildfire if we wish to protect public health.

A wide range of toxic contaminants can get into water supplies via several routes as a result of wildfires. Burned exposed soil and ash can get blown or washed into waterways and carried downstream into rivers and lakes, resulting in pollution of these waterbodies. Additionally, fire-fighting foam typically used in built up areas contains highly toxic carcinogenic chemicals such as PFAS, also known as forever chemicals - for good reason, as they persist in the environment for tens if not hundreds of years — where they have pose a serious health risk to drinking water supplies across the US.

Scientists are now beginning to gain a clearer understanding of how wildfires can contaminate a water distribution network. Searing heat from fires can melt or degrade plastic water pipes, releasing hazardous toxic compounds into water flowing through the pipes, compromising water quality throughout the entire water network. Damaged or cracked pipes can cause water pressure to drop, creating a vacuum that can suck soot, ash and toxic chemical pollutants into the water pipes as the building burns.

According to Andrew Whelton, an associate professor of civil, environmental, and ecological engineering at Purdue University in Indiana, and co-author of the study published in AWWA Water Science, the Tubbs Fire, which burned in northern California for 123 days, destroying 5,600 structures and taking 22 lives, "was the first known discovery of widespread organic chemical contamination in a water distribution system, not just the source water, after a wildfire."

In the aftermath of the Tubbs and Camp Fires, drinking water supplies continued to be contaminated with benzene at levels deemed unsafe even after water utilities replaced the service water lines at a cost of over $44 million in Santa Rosa alone.

It is now two years since the Camp Fire ravaged the town of Paradise, yet drinking water advisories remain in effect for many residents living in Butte County. Alarmingly, despite warnings issued by the local health authority, a survey conducted on Paradise Irrigation District water users six months after the fire revealed that less than 50% of the surveyed participants believed that their drinking water quality had been compromised by chemical contaminants originating from the fire.

As wildfires continue to burn down communities and researchers shed more light on how these fires compromise drinking water quality, we are likely to see more drinking water advisories issued by local water utilities, some of which could remain in effect for many years ahead. This essentially leaves residents without access to a clean and safe supply of drinking water as they deal with the arduous task of rebuilding their homes and lives from the ashes. In situations such as this, having a good quality home drinking water filter that is capable of removing toxic chemicals such as benzene and other VOCs can prove to be an invaluable lifeline, ensuring you and your family always have a reliable source of safe drinking at your disposal.