The Los Angeles wildfires created another problem—unsafe drinking water

Depressurization, another major contributor to contamination, occurs when firefighting efforts draw large amounts of water from the system in a short period of time. “A water line connecting to a house can typically put out about 9 gallons per minute,” says Wilton. “Firefighters can pump 500 gallons or 1,500 gallons of water per minute. So if you’re going to run five or six pumper trucks off a water line, you’re looking at thousands of gallons of water being pumped out of the water system in a very short amount of time.”

When this happens, the water pressure drops and the system becomes vulnerable to bacteria or chemicals entering the system from the surrounding environment. Generally, the high water pressure inside the system prevents any outside contaminants – such as soil or groundwater – from being able to find their way inside the system components.

Structural damage from fire can also cause stress damage, Wilton said. In the case of large scale fires like the Palisades or Eaton fires, you can have large amounts of water dumping, uncontrolled, out of the system due to burst pipes and other parts of the system. Where damage occurs, smoke and debris can be sucked into the water system, while damaged sewer lines can leak into nearby drinking water pipes. “When the water system utilities start trying to suppress, they start pushing that contaminated water back through the infrastructure,” says Whilton.

During the 2021 Marshall Fire in Louisville, Colorado, which burned more than 1,000 homes, city officials advised residents to use mains water only for flushing until extensive testing confirmed safety. With more than 12,000 structures burned in Los Angeles as of Monday morning, the potential for widespread contamination is significant, Cairns warned.

The coming days and weeks will be crucial. Once water experts assess the damage, they will determine if the system can be cleaned or if infrastructure repairs are needed. If enough is burned, workers will have to replace pumps, pipes and even tanks. For parts of Los Angeles County served by LADWP, McCurry estimates this recovery could take anywhere from days to weeks.

Altadena and surrounding areas, however, are served by multiple smaller water providers, viz Lincoln Avenue Water Company, Las Flores Water Company, Rubio Canon Land and Water AssociationAnd Kineloa Irrigation District—All who have issued do drink notices. “In a large water system like the LADWP, you’re probably going to see things start up a little faster,” Cairns said. “For smaller water suppliers, who may sometimes only have a few employees and don’t have the budget for these types of events, they may have some struggles.” Santa Cruz faced similar challenges during the CZU Lightning Complex Fire in 2020, taking months to stabilize water service. McCurry warned that it could take years to build from scratch in some areas or overhaul large systems that have burned down.

It’s vital for residents to stay informed about recovery efforts, as warning systems can be complicated and many residents may not even be aware of them, Cairns said. People should “actively look for any boil or do not drink warnings from your water supplier, your city, your county,” he advises. “Share them with your neighbors and make sure anyone who may have a language other than English as a first language gets those warnings and understands what’s going on.”

Some places, such as Louisville, Colorado, and Maui, Hawaii, have released public access maps that track water quality on each plot of land, helping to keep residents informed in the months and years that follow.

Before lifting advisories, the state of California legally requires water suppliers to monitor for benzene. However, Huelton cautions that benzene is not the only chemical of concern, and the list of potential contaminants is long. Both government and third-party testing services are not always responsible for every potential exposure. “It’s possible that some of those chemicals may be around longer than water suppliers expect,” echoes McCurry. He still advises caution. Activated charcoal filters can help remove some organic contaminants, but they cannot completely eliminate the risk.

“Safe water can There will be restoration after the fire,” Whelton said. “Communities that recover faster and stronger are those that work together and support each other.”