When wildfires spread across California, they leave a cascade of water problems in their wake: Some communities have their drinking water poisoned by toxic substances. Others wrestle with ash and debris washed into reservoirs and lakes. And many living in remote stretches of the state struggle with accessing enough water to fight fires. 

Drinking water has been contaminated with hazardous chemicals after at least three California wildfires in recent years: in Santa Rosa after the Tubbs Fire in 2017, in Paradise after the Camp Fire in 2018 and now in parts of the San Lorenzo Valley burned by the CZU Lightning Complex Fires that began in August. 

The cost of fixing the damage to water systems: up to $150 million in just one small town. 

Towns and water agencies also are grappling with advice to give residents in fire-ravaged areas, who are confused by warnings that seem to continuously change about whether their water is safe. 

In a state plagued by water shortages, rural California has suffered a cascade of water woes in the wake of wildfires that is likely to happen again and again.

The problems now encountered in California are far beyond the scope of regulations protecting drinking water, said Darrin Polhemus, deputy director of the State Water Resources Control Board’s Division of Drinking Water.

“The Safe Drinking Water Act doesn’t have a clause like, ‘This is what you do in a fire when a community is completely burned to the ground,’” he said.

There are 23 major wildfires burning in a record-breaking season that has torn through more than 4 million acres of California, killing 31 people and destroying more than 8,400 structures. 

“It’s safe to bet that with this year’s fire season the way it is, winds picking up and the magnitude of fire that we’ve got, we’re going to see more (water) systems like this,” said Daniel Newton, assistant deputy director of the state water board’s Division of Drinking Water. “The number of fire impacts I am starting to hear throughout the state is staggering,” he added.

The threat to water in the West doesn’t stop when the flames go out. Roughly two-thirds of its water supply flows from forests that can burn. And uncontrolled conflagrations can increase erosion and pollutants that rush into the lakes and reservoirs supplying Californians with water. Researchers project that fire could more than double the sediment clogging a third of Western watersheds by 2050.

“From a water perspective, this is just when the problems are all about to begin — when we put the fire out,” said Kevin Bladon, associate professor of forest ecohydrology and watershed science at Oregon State University. “We can see effects (on water) persist for decades.”

The first clues that fires could contaminate pipes with chemicals came in the fall of 2017 in Santa Rosa, where the Tubbs Fire had destroyed roughly 3,000 homes and commercial buildings. 

Testing revealed contaminants, including benzene as high as 40,000 times the state’s limits, according to a recent study led by Andrew Whelton, an associate professor of civil, environmental and ecological engineering at Purdue University.

Long-term exposure to benzene, a component of crude oil and gasoline, is a well-proven cause of leukemia, and immediate, high exposure can cause dizziness and stomach ailments. 

Drinking water in Paradise also was contaminated with chemicals including dangerous levels of benzene — at least 2,200 times the state limit in one sample, Whelton’s study reports — when the Camp Fire killed 85 people and destroyed nearly 19,000 buildings in Butte County in 2018. Nearly two years later, the town’s utility warns that water connections to unoccupied houses and empty lots may still be contaminated.   

The tab for combating Paradise’s contamination has hit an estimated $50 million, plus $80 to $100 million for additional repairs, Mickey Rich, information systems manager with the Paradise Irrigation District, told CalMatters. The district is seeking federal and state emergency funding, and has tapped into insurance to help pay for the repairs.

“Our goal is to get everything paid for by emergency funds that we can. We don’t feel like our customers should have to pay for any of this damage,” Rich said. 

Stefan Cajina, north coastal section chief of the water board’s drinking water division, said that drinking water officials usually reserve issuing stricter guidance around showering and bathing for when they know for certain the water is contaminated.

Now the state is considering reversing that approach to recommend water systems start with more stringent cautions, and scale them back as test results show the water is safe. 

As California heads into the rainy season, the threats to drinking water will be amplified. Rains may extinguish wildfires, but they can also wash contaminants into water sources.  

Fires kill plants, increasing runoff and accelerating snowmelt. Burning soil can also change its structure, trigger erosion and leave behind layers of ash and debris that flow into streams and lakes.

Wildfires Threaten Rural Towns with Tainted Water

After the 2007 Zaca Fire, the organic material clouding Cachuma Lake jumped by 165%. And it still hasn’t returned to historic lows. Near Redding, water from Whiskeytown Lake grew roughly 20 times dirtier after the Carr Fire. 

All that material can challenge downstream treatment plants to cope with the added mud and altered water chemistry, and it may fuel algal blooms. But adding chlorine to treat the water can kick off chemical reactions with all the additional organic matter to form disinfection byproducts linked to health problems, including bladder cancer.

More of the ingredients that form these disinfection byproducts were found in Northern California creeks after the Rocky and Wragg fires burned through the region in 2015, according to a recent study. 

“It’s very common that in rural parts of California that water is difficult for us,” said Daniel Berlant, an assistant deputy director with CalFire, the state’s firefighting agency. “I’ve been on a number of fires, where communities — even communities you would think are more urban — that just because of the amount of water being used, the water supply and the pressure goes down.”  

It’s why CalFire sends water tenders that can carry water to wildfires, engines are equipped with pumps to pull from lakes and pools and helicopters can swoop in. 

Paradise is leading the way to fireproof its water. “You hope no city ever has to go through this. The good that I see is we got a lot of the research done and we have a lot of the answers now,” Rich said. 

The state, too, is working on developing its playbook for water systems to ensure they’re prepared to immediately flush pipes, isolate burned neighborhoods and test for contaminants. 

 

Rachel Becker is a reporter with a background in scientific research.