Decompression, another significant cause of contamination, occurs when huge amounts of water are withdrawn from a system in a tiny period of time during firefighting. “The water line connecting the house can typically release about 9 gallons of water per minute,” Whelton says. “Firefighters can draw 500 gallons, or up to 1,500 gallons of water per minute. So if you remove five or six pumping stations from a water supply, thousands of gallons of water will be taken from the water supply in a very short period of time.”
When this happens, the water pressure drops dramatically and the system becomes susceptible to bacteria or chemicals entering the system from the surrounding environment. Typically, high water pressure inside the system prevents any external contaminants, such as soil or groundwater, from entering the system components.
Structural damage from fires can also result in pressure loss, Whelton says. Gigantic-scale fires, such as the Palisades and Eaton fires, can cause huge amounts of water to leak uncontrollably from the system as pipes and other parts of the system rupture. In the event of damage, smoke and pollutants may be sucked into the water system, and damaged sewer lines may enter nearby drinking water pipes. “When the water utility starts trying to increase the pressure, it starts pushing contaminated water through the infrastructure again,” Whelton says.
During the 2021 Marshall Fire in Louisville, Colorado, which burned more than 1,000 homes, city officials advised residents to employ mains water only for flushing until extensive testing confirmed safety. Given that more than 12,000 buildings had burned in Los Angeles as of Monday morning, the potential for widespread contamination is significant, Kearns warns.
The coming days and weeks will be crucial. Once water experts assess the damage, they will determine whether the system can be flushed spotless and whether infrastructure repairs are needed. If enough has burned, workers will have to replace pumps, pipes and even tanks. For parts of Los Angeles County served by LADWP, McCurry estimates it could take days to weeks to return to normal.
However, Altadena and surrounding regions are served by many smaller water providers such as Lincoln Avenue Water Company, Las Flores Water Company, Rubio Canon Earth and Water AssociationAND Kinneloa Irrigation District— all issued no-drinking warnings. “For a large water system like LADWP, things will probably reopen a little quicker,” Kearns says. “For smaller water providers who sometimes have just a few employees and don’t have the budget for these types of events, they may have some difficulties.” Santa Cruz experienced similar challenges during the CZU Lightning Elaborate fire in 2020, and it took months for water supplies to stabilize. McCurry warns that in some regions it could take years to build from scratch or renovate huge systems that have burned.
It’s essential that residents stay informed about remediation efforts because warning systems can be complicated and many residents may not even receive them, Kearns says. People should “actively seek out any boil water notices or drinking bans from their water supplier, city or county,” he advises. “Share these notifications with your neighbors and make sure all non-English first language speakers receive these notifications and understand what is happening.”
In some places, such as Louisville, Colorado, and Maui, Hawaii, public maps were published to track water quality on each property, which helped keep residents informed in the months and years to come.
Before lifting the advisory, California has a legal obligation for water suppliers to monitor benzene levels. However, Whelton 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 do not always account for every possible exposure. “It is possible that some of these chemicals will remain in the water longer than water suppliers expect,” McCurry reiterates. He still recommends remaining vigilant. Activated carbon filters can assist remove some organic contaminants, but may not completely eliminate the risk.
“Safe water Power be restored after the fire,” Whelton says. “The communities that recover faster and stronger are those that work together and support each other.”