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Wildfires and Water Quality: VOC Contamination

By Alisen Boada

After several years of catastrophic wildfire seasons on the West Coast, we are learning more about the hazardous impacts these disasters have on local drinking water. 

Local drinking water after California’s Tubbs Fire (2017) and Camp Fire (2018) contained benzene and other toxic volatile organic compounds (VOCs) at levels above legal water quality limits. After widespread VOC contamination, boiling advisories and filters are not enough to protect residents. So, what can homeowners and public health officials do to make sure local water supplies are safe after a massive wildfire? We’ll discuss what causes VOC contamination and steps to help gauge whether your plumbing and private wells are safe. 

The Health Risks of Wildfire Contamination

As we discussed in our post from 2017, wildfires can overwhelm water treatment centers with sediment—and effects reach as far as 100 miles from the fire center. But wildfires pollute water sources with more than just ash and other debris.

The Tubbs and Camp Fires were among the deadliest in California’s history, and drinking water tests after the tragic destruction of local communities revealed unsafe levels of VOC contamination.

VOCs are a variety of chemicals linked to a range of health issues including cancer. While many of these risks come from long periods of exposure, the chemical levels found in local water supplies were high enough to cause even short-term health effects—like vomiting, diarrhea, and nausea.

Both fires resulted in dangerous levels of several VOCs including:

  • Naphthalene
  • Tert‐butanol
  • Toluene
  • Vinyl chloride
  • Concentrations of benzenea known carcinogen—were found at 40,000 parts per billion (PPB) after the Tubbs Fire and more than 2,217 PPB after the Camp Fire. 

    California health agencies have stated that children exposed to benzene levels as low as 26 PPB can experience short term health effects. Because cancer is long-term risks of benzene exposure, California’s Public Health Goal for benzene in drinking water is 0.15 PPB (which is about the equivalent of less than 1 drop of water in an Olympic-sized swimming pool). 

    How Do Wildfires Spread VOCs to Drinking Water?

    The Tubbs and Camp Fire in California are the first studied cases showing widespread chemical contamination in the water distribution network itself and not in the source water. Pipes inside buildings and buried underground were heavily contaminated.

    More research is needed, but evidence currently suggests that this contamination came from a mix of burning vegetation, structures, and plastic materials

    Wildfires like these are so hazardous and destructive because they happen in areas where human development meets wildlife. These events fall into a category of hazards called “Natech,” or natural disasters that lead to technological disasters, like the release of toxic chemicals.

    How Can You Tell If Your Water Is Contaminated After a Wildfire?

    Health officials are still putting together policies for keeping residents safe after major wildfires.

    However, agencies have struggled to perform sufficient water testing following these disasters. 

    After the Camp Fire, California officials told residents to check for odors to indicate whether there were harmful chemicals in the water—even though VOCs like benzene can create health risks at lower concentrations than what’s detectable by smell.

    Water quality experts have stated that only testing can determine safety, and that all buildings should be tested after a wildfire. Reliable testing also needs to include samples of both hot and cold water from many taps in a building because water quality can vary greatly between rooms.

    It’s also important to note that most utilities are responsible only for testing the service lines up to the customer’s connection (typically at the curb box/water meter). Customers are responsible for testing the water quality in their homes after that connection point.

    How To Protect Drinking Water After a Wildfire

    After the Camp Fire, researchers estimated that some plastic pipes needed more than 280 days of flushing before they were safe to use again. As of March 2020, 8.5% of water tests still detected benzene and/or other VOCs.

    For areas that have gone through a major wildfire, “do not use” orders can keep people safe until local health agencies can test the water.

    Boiling advisories and household water filters are not enough to protect residents from highly contaminated water.

    Does Boiling Water Remove VOCs?

    Boiling tap water is only effective for certain VOCs, and should not be relied on as a treatment option.

    Because VOCs easily evaporate, these chemicals aren’t only a health risk for drinking—boiling water (and even hot showers) can vaporize VOCs and create air quality hazards. 

    Can Water Filters Remove VOCs?

    Activated carbon filters can remove many VOCs, but these filters may not be suitable for the high levels of chemical contamination after a wildfire. 

    Carbon filters need to be monitored and replaced more frequently when they are treating high or repeated doses of contamination. Point-of-use (POU) carbon filters—like those used in refrigerators and on faucets—have an even shorter life span than whole house filters. 

    All filters should go through frequent testing while local drinking water is contaminated. The EPA’s guidance for Point-of-Use or Point-of-Entry Treatment Options suggests monitoring filters monthly.

    It’s also important to note that POU devices only protect the taps they are filtering. In addition to posing an air quality hazard, some VOCs can also be absorbed through the skin. This leaves water coming from shower heads and other untreated household faucets a potential hazard.

    Can Wildfires Contaminate Private Wells?

    Private wells are also at risk of damage and contamination from wildfires. You should always test your well water after any changes in water appearance, clarity, color, smell and/or taste.

    Test your water now

    Contact a licensed well contractor if you see any of damage to:

  • Electrical wires and connectors that supply power to your well
  • The well casing and above-ground piping
  • Chlorinators, water treatment equipment, and electronic controls
  • Pressure tanks that could have been exposed to excessive heat
  • Storage tanks, vents, and overflow pipes
  • Check for damage to plumbing inside your home by making sure the well system maintained positive pressure during the fire. If you hear air escaping or water sputtering while running a faucet, that is a sign that your well and household plumbing had a loss of pressure and may have been damaged.

    If a well system is damaged during a wildfire, it may be at risk contamination from chemicals and microorganisms

  • Fire retardant used near a wellhead can potentially contaminate the system, especially if the wellhead is damaged. Monitor ammonia and nitrate levels for several months.
  • After the Camp Fire, Butte County recommended that well owners near creeks and rivers test for elevated levels of heavy metals (like Aluminum, Arsenic, and Cadmium).
  • If the fire reached the well, pressure tank, or any exterior plumbing including buried plastic piping, the county recommended testing for benzene. 
  • Preparing for Future Wildfires and Contamination

    Wildfires create long lasting water quality challenges for communities and the agencies and utilities responsible for keeping them safe.

    In California alone, more than 2.7 million people live in very high fire hazard severity zones

    The effects of large scale wildfire destruction in urban areas are still being studied. It may take years before we fully understand the impacts of the chemicals being released into the environment from human-made materials (like personal care products, metals, and plastics).

    Contact the Tap Score team of treatment experts, water quality engineers, and chemists any time using the live chat or sending them an email at hello@simplewater.us. They can help answer any questions about VOCs or any other water quality issues that you may have. 

    Sources and References

    What Do Wildfires Mean for My Water Quality?

    Wildfire Impacts on Water Quality

    Wildfire caused widespread drinking water distribution network contamination

    What Are VOCs and Are They in Your Drinking Water?

    Naphthalene

    Hazardous Substance Fact Sheet

    Public Health Statement: Toluene

    Vinyl Chloride - Cancer-Causing Substances

    CDC | Facts About Benzene

    Estimated Risks from Short-term Exposures to Benzene in Drinking Water

    Chemical releases caused by natural hazard events and disasters

    Opinion: Amid a Water Crisis, California Officials Fan Flames of Confusion

    Wildfires can poison drinking water – here's how communities can be better prepared

    Study: Your home’s water quality could vary by the room – and the season

    FINAL Page 1 of 10 CONSIDERATIONS FOR DECONTAMINATING HDPE SERVICE LINES BY FLUSHING 1. With continuous/intermittent flushing,

    What is the difference between PEX and PB pipes

    Activated Carbon (Charcoal) Filters

    POE Versus POU Water Treatment | SimpleLab Tap Score

    Point-of-Use or Point-of-Entry Treatment Options for Small Drinking Water Systems, April 2006

    Frequently Asked Questions (FAQ) - Wildfire Response | Central Valley Regional Water Quality Control Board

    Wildfires Can Damage Water Wells - EH

    Addressing the Impacts of Wildfire on Water Resources

    Post-Fire Well Safety and Testing Guidelines

    7 Heavy Metals Everyone Should Test For | SimpleLab Tap Score

    Analysis: Safety rules give homes better chance in wildfires

    A growing problem after wildfires: Toxic chemicals - The Washington Post

    Personal Care Products: Everyday Pollutants on Your Body

    North Bay wildfire ash may contain toxic metals, other health hazards

    It's hard to get trustworthy advice when it comes to your drinking water, so we made Tips for Taps to help answer your questions. Order a Tap Score Water Test and receive personalized support from professional engineers and scientists by phone, email and chat.

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