Wildfires Can Contaminate Public Drinking Water Systems for Years

Last updated: September 14, 2026

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

More than 8,000 wildfires devastated over 4 million acres across California in the 2020 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 residents at immediate risk from 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 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.

Benzene in Paradise: What the Camp Fire Water Samples Showed

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 irritation to more serious effects on the immune, reproductive and nervous systems and developmental problems in children. Long-term exposure to these chemicals can cause cancer.

How Wildfires Contaminate Water Supplies

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

A wide range of 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. Research led by Fernando Rosario-Ortiz at the University of Colorado Boulder has shown that heated soils release more dissolved organic carbon and nitrogen compounds, which can react with treatment chemicals to form regulated disinfection byproducts, while the most severe burns shift the problem toward heavy sediment loads that strain treatment plants. Additionally, fire-fighting foam typically used in built-up areas contains carcinogenic chemicals such as PFAS, also known as forever chemicals, which persist in the environment for decades and pose a serious 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 compounds into water flowing through the pipes and compromising water quality throughout the network. Damaged or cracked pipes can cause water pressure to drop, creating a vacuum that can suck soot, ash and chemical pollutants into the water pipes as a building burns.

According to Andrew Whelton, a professor of civil, environmental, and ecological engineering at Purdue University in Indiana and co-author of the AWWA Water Science study, 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."

Advisories Can Last for Years

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 service lines at a cost of over $44 million in Santa Rosa alone.

Two years after the Camp Fire ravaged the town of Paradise, drinking water advisories remained in effect for many residents of Butte County. Alarmingly, despite warnings issued by the local health authority, a survey of Paradise Irrigation District water users six months after the fire revealed that less than 50% of participants believed their drinking water had been compromised by chemical contaminants from the fire.

As wildfires continue to burn through 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 years. Once a utility lifts its advisory, residents who want an added layer of protection at the tap for chemical contaminants such as benzene and other VOCs can look at what independent labs have measured for the Black Berkey and Berkey Phoenix Elements.

Frequently Asked Questions

Is tap water safe to drink after a wildfire?

Not automatically. After the 2017 Tubbs Fire and 2018 Camp Fire, benzene and other VOCs were found inside water distribution pipes, not just source water, at levels far above the federal 5 ppb benzene limit. Follow your utility's advisory; if a "do not drink" or "do not use" order is in effect, use bottled or trucked water until the utility confirms testing has cleared the system.

What contaminants do wildfires put into drinking water?

Ash, sediment and dissolved organic carbon from burned watersheds, which can also form disinfection byproducts during treatment; VOCs such as benzene, toluene, styrene and naphthalene released from heat-damaged plastic pipes and drawn in through depressurized lines; and PFAS from certain fire-fighting foams.

How long do wildfire water advisories last?

It varies with the extent of pipe damage. Paradise, California still had advisories in effect for some residents two years after the Camp Fire, even after major service-line replacement, because benzene kept leaching from damaged plumbing.

Can a home water filter remove benzene after a wildfire?

Some filters are tested for VOC reduction, but no home filter replaces a utility's flushing and testing program during an active advisory. Once the advisory is lifted, check independent lab data for the specific filter. Black Berkey and Berkey Phoenix Elements have been tested by independent laboratories for benzene and other VOCs; the reports are on the test results page.