Unsafe to drink: Wildfires threaten rural towns with tainted water

In a state already plagued by water shortages, the problems in rural California are likely to happen again and again as climate change primes the West to burn.

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.

‘We’re going to see more systems like this’

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. 

Since the 1980s, climate change has more than doubled the hot and dry conditions that combine to create extreme fire weather, according to new research. 

At the same time, more Californians are in harm’s way: between 1990 and 2010, the number of houses built at the edge of nature increased by more than a third. And 640,000 to 1.2 million new homes could pop up in the state’s highest fire risk areas by 2050.

That means more fire survivors could come home to find their pipes burned and their water undrinkable. 

“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.”

Problems in the pipes

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. 

Soon after residents returned to the remaining houses, Santa Rosa Water received a complaint: The water smelled and tasted strange, according to city memo.

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. 

The source of the contamination, the city’s investigation concluded, was the wildfires. Burned plastic piping can release benzene and other chemicals, as can homes going up in smoke. Water systems depressurized during fires may suck in those compounds, which then soak into plastic pipes and coat metals and other materials. 

The damage can linger for years because cleaning it up requires removing poisoned pipes and extensively flushing the system, according to Whelton.

“There is no good approach,” Whelton said. “The rudimentary approach of just flushing water is there because nobody’s really developed better solutions.” 

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. 

Confusing, shifting warnings

Napa County engineering manager Christopher Silke, who also oversees the private contractor operating Berryessa Highlands’ tiny water district, hopes that his team’s quick action saved the community’s water system from a similar fate.

After the fire, the lines serving burnt properties were capped, leaks were fixed and the system repressurized and flushed. The district issued a warning to boil the water before drinking it because of potential bacteria. 

But two weeks later, the state warned of the potential for contamination with chemicals like benzene, and told the district to change the warning to caution against drinking or boiling the water. The notice the district issued said that people may also want to limit showering and hot water use. 

Silke immediately sent out orders to pull out the water meters where public and private plumbing intersect, and retrofit meter boxes to allow flushing but prevent backflow from the burned properties. 

Although drinking water is uncontaminated with benzene and similar chemicals so far, Silke pledged to continue monitoring. “This is public health,” he said. “We need to be vigilant.”

Advice to residents also shifted after the CZU Lightning Complex Fires in Santa Cruz and San Mateo counties. The San Lorenzo Valley Water District issued a ‘do not drink/do not boil’ warning, then updated the guidance days later to recommend avoiding baths and limiting showers to lukewarm water. Residents were confused, asking at a public meeting why the district didn’t warn them against washing with the water  right away. 

Whelton, the environmental engineer at Purdue, would have preferred immediate warnings against showering and bathing, particularly since one San Lorenzo Valley neighborhood had 42 times more benzene than state limits allow. 

Chemical levels dropped below the state’s standard after the pipes were flushed, Newton said. But Whelton said that testing after wildfires should continue for long periods, and should be expanded to more chemicals.

He also worries that the failure to rapidly warn people against bathing in potentially contaminated water led to precisely the predicament Petrini found himself in when weighing how to wash baby Levi. 

“You have to issue water advisories and orders that don’t allow infants and children to be exposed to contaminated water,” Whelton said. “This isn’t complicated. After a disaster, the infrastructure may be damaged, you issue a ‘do not use’ order.” 

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. But “that has turned out to be a really confusing and uncomfortable message for the public to hear,” Cajina said.

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. 

“Bottom line, water systems may want to be told what to do in these situations, and we do our best to provide solid guidance, but they are ultimately responsible,” he said.

When the fires stop, the rains start

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.  

“Really what’s going to determine how ugly things get and how concerning they get for both the health of our ecosystems and for our communities are those first rain events that we’re going to get this fall, and really the first couple of years,” Oregon State University’s Bladon said. Particularly if vegetation hasn’t had a chance to regrow on slopes scoured by wildfires.

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.

“Every drop of water in a watershed basically is moving towards that outlet,” said Newsha Ajami, director of Urban Water Policy at Stanford University. “And if they’re not cleaned up, all those pollutants and contaminants and toxins can end up in our water system.”

Sediment slicking down fire-denuded hills can fill reservoirs, squeezing out space for the water. In Santa Barbara County, the Gibraltar Reservoir has lost roughly 50% of its storage capacity over the past 20 years, largely due to increased sedimentation from wildfires, according to Joshua Haggmark, Santa Barbara’s water resources manager. 

After the 2007 Zaca Fire, the organic material clouding Cachuma Lake jumped by 165%. And it still hasn’t returned to historic lows, Haggmark said. 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. 

In Napa County, Silke has encountered increased sediment repeatedly in Lake Berryessa after previous wildfires, and he’s bracing for problems at the treatment plant in the months ahead. 

“If you took a coffee filter, and tried to make several batches of coffee with that filter, what’s going to happen then? It’s going to plug up,” he said. It’s the same with turbid water. 

Producing 100,000 gallons of drinking water from the murky lake can churn out about 40,000 gallons of sludge, he said. And that puts a bigger strain on the wastewater treatment plant, as well. 

Silke has designed a $180,000 treatment step to help the mud and silt settle out of Berryessa Highlands’ water. The cash-strapped water district is looking to California’s Office of Emergency Services for help. 

“We’re going to have to find a way,” Silke said. 

Petrini worries that the wreckage of his home will be among the debris tumbling towards Lake Berryessa this winter if the clean-up process continues to lag.

“Rains are coming soon,” he said. “And if we don’t get our lots situated, it’s going to cost us tens of thousands of more dollars just to get them regraded after the hills start sliding down on themselves.”

Water pressure drops

On a hot September morning, Berryessa Highlands residents gathered outside the volunteer fire station to voice their water woes. A standout concern, particularly from residents who bucked evacuation orders to defend their homes, was the restricted flow from hydrants. 

It happened to Daniel Williams, who helped defend his father Stu’s house. Perched on the roof with a fire hose, Williams, 41, was spraying the embers when the water flow died. 

“It was like, well what else do you want to throw at me? I’m doing everything I can,” he said. “It just made no sense that there’s this big body of water, but we have no water pressure on top of our roof to fight the fire.” 

The Williams’ house survived; at least 93 others did not. Testing in August revealed that five of the development’s 67 hydrants had possible mechanical problems, according to Annamaria Martinez with Napa County. But Napa County Fire Chief Geoff Belyea told CalMatters that despite pressure fluctuations, firefighters had enough water to battle the flames. 

Readouts of the lakeside water treatment plant’s activity show the pumps kept pumping, Silke said. But as water gushed from burned homes and firefighters and residents trained hoses on the flames, the 500,000-gallon ridgetop storage tank that maintains pressure in the pipes dropped to critically low levels, according to Silke. 

“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. 

And it’s why CalFire and drinking water officials warn against residents leaving sprinklers on as a fire approaches. Not only does it diminish the water firefighters can use, but it also can prime the depressurized pipes for contamination.

“Rural residential community public water systems were never designed with the intent to provide a line of wildfire defense to save structures,” Silke said. 

Jennifer Clary, California director of the advocacy group Clean Water Action, said “it’s virtually impossible to build a potable water system that can also fight megafires.” Building a distribution system that is too large can allow the water to stagnate in pipes, which allows disinfection byproducts to accumulate, she said.

Stanford’s Ajami said the key will be rebuilding with resilience. “If you’re going back to build these communities, do you really want to build them the way before?” she said. “Isn’t this a new chance to revisit our planning and development practices?”

For Whelton, that means updating building codes to require concrete water meter boxes rather than flammable plastic ones, and valves that prevent water flowing back from burned houses into the public water system. 

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. 

But getting ahead of the flames is an uphill battle, said the water board’s Polhemus. “We need the fires to quit, before we can even catch our breath.”