In the wake of the devastating wildfires that engulfed Maui, residents in torched areas have been issued a stark warning from Maui County: do not attempt to filter your own drinking water. The county took to their Instagram account this week to inform the public that there is currently no way to make the water safe for consumption. Anne Rillero and her husband, Arnie, residents of Kula who miraculously survived the fires, heeded this warning and have resorted to eating frozen pizza meals on paper plates to avoid any potential exposure to contaminated water.

The extent of the damage caused by the fires is evident in Lahaina, a town that has been largely wiped off the map. The confirmed number of fatalities has been raised to a staggering 114, emphasizing the devastation and loss experienced by the community. The aftermath of the wildfire can be seen in the charred remains of buildings and the damage inflicted on hundreds of drinking water pipes. This damage has resulted in a loss of pressure, allowing toxic chemicals, metals, and bacteria to infiltrate the water lines.

According to experts, popular water filtration methods such as Brita filters, refrigerators or sink attachments, and whole-home systems are unlikely to effectively address the extreme contamination that occurs after a fire. While they may remove some contaminants, levels that are acutely and immediately toxic will inevitably make their way through. Andrew Whelton, a researcher at Purdue University and an expert in water contamination after urban wildfires, warns that these filters may not be enough to ensure the safety of the water.

Maui County has advised residents of Lahaina and Upper Kula, where hundreds of families are facing similar concerns to the Rilleros, to minimize contact with county water, including refraining from taking showers. In Lahaina alone, aerial imagery and damage assessment data reveal that 460 buildings have survived the fires seemingly undamaged. These are the places where people are now returning, and precautions need to be taken to ensure their safety.

The state health department's environmental health division has instructed Maui County, responsible for the water delivery systems, to conduct tests for 23 chemicals in the water. These chemicals are those for which the federal government has set limits for drinking water. These warnings reflect a new understanding of the science behind water contamination after wildfires and aim to avoid the confusion and conflicting information that impacted those affected by the 2018 Camp Fire in California.

Historically, it was only believed that wildfires could contaminate drinking water at the source, such as when ash runs into a river or reservoir. However, recent studies, including one by Whelton and the American Water Works Association, have shown that widespread drinking water chemical contamination has been discovered in the water distribution network after fires like California's Tubbs Fire in 2017 and the Camp Fire. This revelation has prompted a reevaluation of previous protocols, as it was initially believed that boiling water after a fire would suffice. However, as seen in the case of the Camp Fire, smoke and chemicals can easily leach into the water through broken and melted water pipes, necessitating more stringent measures.

The wildfires have also revealed the presence of new contaminants. Hawaii's state government has instructed Maui County to test for volatile chemicals, which tend to become airborne like gasoline vapor. However, Whelton's research on the Marshall Fire in Boulder County, Colorado, has shown that a group of heavier compounds known as “semi-volatile” can also contaminate damaged water lines even when better-known chemicals like benzene are not present. This discovery further highlights the complexity of water contamination after wildfires and the challenges faced in ensuring its safety.

For residents on Maui who rely on private wells for their water supply, experts advise getting the water tested. In the event of a fire near a well, the cap may be damaged, allowing debris to enter. Additionally, the plastic lining of the well can melt, releasing hazardous fumes into the water. Despite the immense challenges ahead, experts caution against rushing the restoration of safe water, emphasizing the need for thorough and repeated validation of water quality to avoid any potential health risks.

The road to recovery will undoubtedly be long and arduous for the residents of Maui as they rebuild their lives amidst the ruins left by the wildfires. However, with proper precautions, ongoing testing, and a commitment to public safety, the community will hopefully be able to overcome the challenges posed by the contaminated water supply. In the meantime, organizations and volunteers continue to provide support to those affected, unloading donations and working to aid in the recovery efforts.