Drinking water safety at risk after Los Angeles fires

Wildfires could contaminate Los Angeles water with harmful chemicals

Written by Andrew J. Welton & The Conversation US

The following essay is reproduced with permission. The Conversation is an online publication covering the latest research.

Firefighters continue to battle an inferno as wildfires in the Los Angeles area destroy thousands of structures, including many homes. Pacific Palisades, Altadena, Pasadena, and some other California communities are now unrecognizable.

As evacuation orders are lifted, securing safe drinking water will be a top priority for residents returning to their homes.

About supporting science journalism

If you enjoyed this article, please consider supporting our award-winning journalism. Currently subscribing. By subscribing, you help ensure future generations of influential stories about the discoveries and ideas that shape the world today.

What many people don’t realize is the extent to which local drinking water systems can be damaged by fire, how water is affected, and what can be done about it. That’s it.

As an environmental engineer, I work with communities affected by wildfires and other disasters. For many years, my team and I have been called to rescue after some of the most destructive wildfires in U.S. history. In some cases, we have advised state and local officials from afar.

Several local water systems in the Los Angeles area have begun issuing warnings against using potentially unsafe drinking water. Here’s what area residents and those living near wildfire sites need to know:

How water becomes dangerous due to fire

A fire can make not only drinking water unsafe, but also the water pipes and tanks themselves. This can happen for various reasons.

One cause is that water systems are drained due to the large amounts of water used by firefighting operations.

Water systems are not designed to fight wildfires. Damage or destruction of buildings can also cause uncontrollable water leaks. Power loss also prevents water from refilling the drainage system quickly enough. A combination of these factors can depressurize the water supply system and make water unavailable.

When water is depleted, the system becomes susceptible to chemical contamination.

Contamination of drinking water can also occur from damage to air or water infrastructure. The heat can partially melt plastic pipes and water meters, releasing chemicals. Smoke can be inhaled into water systems. And damage to water infrastructure can cause pollution.

Numerous carcinogenic chemicals have been found in damaged water systems after wildfires. Chemicals such as benzene can cause immediate illness if you drink or use the water. Symptoms include nausea, headache, and rash.

These chemicals can adhere to infrastructure surfaces and even penetrate some plastic pipes and gaskets. Their removal can take anywhere from a few days to a few months. Some plastics, like sponges, can absorb chemicals and slowly release them into clean drinking water, making the water unsafe for long periods of time.

How communities can reduce risk

Residents and businesses should pay attention to announcements from drinking water providers and health authorities regarding water safety.

Safety can be determined by appropriate chemical testing. Fortunately, the first-ever guide to water systems for responding to and recovering from fires was published in 2024. Property owners can get more information from groups like Purdue University’s research team.

When to test and treat your water

Care must be taken when testing household drinking water.

After the wildfires in Maui, Hawaii in 2023 and the Camp Fire in Paradise, California in 2018, I spent hundreds to thousands of dollars hiring companies to conduct their own water quality testing. I met with many families. However, many of the results turned out to be irrelevant. In some cases:

• Residents were charged for water analysis even though the samples were improperly handled.

• Potentially contaminated water was dumped from the piping before samples were collected.

• Water samples were not accurately tested for fire-related chemicals.

• Samples were not collected from appropriate or sufficient locations within the home.

Treatment of the water is not recommended until the level of contamination is known. The region’s water system has issued such warnings.

Residents should also be aware that home water treatment equipment is not certified to make extremely contaminated water safe.

To help property owners make the best decisions, water utilities need to quickly test and share with the public what chemicals are present in their water systems. Once an inspection is conducted and the risks are known, property owners may want to request their own inspection in the event of pipe damage or contaminated water entering.

water systems can be restored

While waiting for information can be frustrating, it is often dangerous for water personnel to enter the affected area to begin testing immediately after a fire.

History has shown us that safe water can be regained. Recovery can be faster if you have support from professionals who have helped others cope. In my experience, communities recover quickly and strongly when they work together and support each other.

This article was first published conversation. please read original article.