Wildfires are contaminating drinking water systems, and it’s more widespread than people realize

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Andrew J. Whelton, Purdue University

(THE TALK) Last year, more than 58,000 fires scorched the United States, and 2021 is on track to get even drier. What many people don’t realize is that these wildfires can do lasting damage away from the flames – they can contaminate entire drinking water systems with carcinogens that persist for months after the fire. That water flows into houses and also pollutes the sanitary facilities.

Over the past four years, wildfires have contaminated drinking water distribution networks and pipeline construction for more than 240,000 people.


Small water systems for housing projects, mobile home parks, businesses and small towns have been particularly hard hit. Most didn’t realize their water was unsafe until weeks to months after the fire.

The problem starts when wildfire smoke gets into the system or heats up plastic in water systems. When heated, plastics can release harmful chemicals, such as benzene, which can contaminate drinking water and enter the system.

As an environmental engineer, I and my colleagues work with communities recovering from forest fires and other natural disasters. Last year, at least seven water systems were found to be contaminated, suggesting that drinking water pollution is a bigger problem than people realize.

Our new study identifies critical issues that households and businesses must be aware of after a wildfire. If you don’t address them, it can harm people’s health – mentally, physically, and financially.

Forest fires make drinking water unsafe

When wildfires damage water distribution pipes, wells and pipes in homes and other buildings, they can cause immediate health risks. A building’s plumbing can become contaminated by smoke drawn into water systems, heat-damaged plastic pipes – or by contamination that enters the plumbing and leaches slowly over time.

Since 2017, multiple fires have left drinking water systems unsafe, including the EchoMountain, Lionshead and Almeda fires in Oregon and the CZULightningComplex, Camp and Tubbs fires in California. Thousands of private wells have also been affected.

Exposure to contaminated water can cause immediate damage such as headache, nausea, dizziness and vomiting. Short-term exposure to 26 parts per billion or more of benzene, a carcinogen, can cause a decrease in the number of white blood cells that protect the body against infectious diseases. The drinking water has exceeded this level due to several fires. A variety of other chemicals can also exceed exposure limits for safe drinking water without benzene.

Households are not sufficiently warned

In a study of 233 households affected by water pollution, we found that people reported high levels of anxiety and stress associated with the water problems. Almost half had installed water treatment in their homes due to uncertainty about the water. Eighty-five percent had looked for other water sources, such as bottled water.

In some cases, we found that advice from government agencies put households at greater risk of harm. It has at times exposed people to chemicals, causing them to spend money unnecessarily and give them a false sense of security. For example, certified in-home water treatment devices are only tested to reduce 15 parts per billion of benzene to less than 5 parts per billion, the federal standard. These devices have not been tested to treat contaminated water to the scale of hazardous waste found after forest fires.

Following the 2020 CZU Lightning Complex Fire near Santa Cruz, California, a local health department correctly warned owners of private wells not to use and test their water, but a nearby damaged water system and the state warned 17,000 people not to in the polluted water. Only after the test results showed that the water had been unsafe all along did the owner and state of the system advise against bathing in it.

In Oregon, some damaged systems encouraged people to boil their drinking water, later discovering that the water contained benzene.

After the 2018 campfire that devastated Paradise, California, the local health department rightly warned the entire county not to use or attempt to treat the drinking water because it was contaminated above the EPA’s hazardous waste limit. But one water system and the state encouraged 13,000 people to treat it themselves.

In all these cases, the US Environmental Protection Agency chose not to force water utilities to explicitly notify customers of the water pollution and its risk.

Communities have received other bad information:

– Commercial labs and government officials recommended flushing faucets for 5 to 15 minutes before collecting a water sample, discarding contaminated tap water intended for testing.

– Homeowners were led to believe that a single cold water sample at the sink would determine if the home’s hot water system and service line were contaminated. It’s not possible.

– People were led to believe that testing with benzene water would determine if other chemicals were present above safe limits. This is not possible.

What to look for after a fire in the area

Signs of possible contamination after a nearby wildfire can include loss of water pressure, discolored water, heat damage to water systems inside and outside buildings, and broken and leaking pipes, valves, and hydrants.

Drinking water should be considered chemically unsafe until proven otherwise.

Once a system is contaminated, it can take months to clean up. The water system will have to be flushed and tested regularly to detect contamination. Health departments should also provide guidelines on testing private wells and plumbing.

When testing plumbing, include the property service line and hot and cold water lines. Before collecting a water sample, the water must sit in the pipes long enough for contamination to be found – 72 hours was the Tubbs Fire and Camp Fire standard. Tests should look for more than just benzene.

Who can help?

Many of the critical public health risks identified in our new study can be addressed by public health departments with funding from state and local agencies.

Public health departments are often experienced in addressing water issues, such as Legionella outbreaks, and can provide technical advice on both chemical exposure, building sanitation and private drinking water wells.

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This article has been republished from The Conversation under a Creative Commons license. Read the original article here: https://theconversation.com/wildfires-are-contaminating-drinking-water-systems-and-its-more-widespread-than-people-realize-159527.

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