How Wildfires Affect Drinking Water

by Caitlin Schott / Sep 24, 2020
How Wildfires Affect Drinking Water

When turning on your TV or thumbing through your phone, you're quick to see the destruction both small and large wildfires cook up. Even if you're not directly in harm's way, wildfires can impact your life. One surprising way fires can impact you is by changing the ecology and hydrology of your drinking water supply. When burn areas are at our source water, the damage doesn’t stay localized. Entire water systems can be impacted, and, in turn, your health can be impacted.

The devastating truth is that these severe wildfires have an immediate and long-lasting impact on the surrounding ecosystems and water supplies.

That's not to say you're sipping ash every time you take a swig. But if you're already concerned about your tap water (like we are), wildfires are alarming. 

While clean water is always top of mind for us, let's make something abundantly clear: Our hearts go out to all of those impacted by these common crises. We'd first like to offer our condolences to families in Colorado, California, Nevada, Australia, and other locations, who have lost their lives, family, friends, pets, possessions, homes, and more to these tragic events.

Wildfires Target Our Water Supplies

We expect clean water to flow like magic with the slight turn, twist, or pull of a handle, and in some cases, it does. But what if the source water is up in flames? Whether we acknowledge it or not, when fires attack our forests, they also attack our water supply

According to the U.S. Geological Survey at, most of the freshwater resources in the United States originate on forested land where watersheds and reservoirs are abundant. Think about this: Nearly two-thirds of the municipalities in the U.S.A. and many of the world's largest cities pull from forested areas. Los Angeles, Tokyo, and Melbourne are just a few on the list. Hits a little close to home, doesn't it? The point is: When forest fires attack, we're all at risk.

The Impact of Wildfires on our Drinking Water

We often consider fires' immediate urgency and danger, but wildfire risks go beyond the first threat. Forest management agencies, like the U.S. Forest Service (, do their best to mitigate the impact of wildfires. Still, even fire retardants and preventative measures can impact our drinking water. Let's take a closer look at the immediate and long-term effects wildfires can have on our water supply.

The Immediate Impact

During active fires, ash, chemicals, and contaminants make their way into and around water systems through streams, lakes, and reservoirs that supply our drinking water.

And let's not forget that these forest fires are often accompanied by rainstorms. This one-two punch of problems only makes matters worse as the precipitation shuttles byproducts like sediment, contaminants, dissolved organic matter, and debris into surrounding bodies of water. Furthermore, as we battle back, firefighting can accelerate the spread of contamination while introducing fire retardant into the mix. Our water supplies can be rife with chemicals, contaminants, and pollutants in the blink of an eye. 

But that's not all: While fires are catalysts for releasing debris flows of sediment, heavy metals, and other contaminants into surface water, they're also leaving behind chemicals as they torch hydrants, meter boxes, pipes, and anything else standing in their way. Melted plastic from pipelines hidden underground and inside structures can pollute the water that flows through. Lenient building codes and limited testing on municipal water supply only enhance the problem. Just like that, more potential hazards — some that cause immediate physical harm and impairment — are added to the list. Sipping on tap water isn't the only way we're at risk. Some contaminants and chemicals can be inhaled or even absorbed through the skin, just by running polluted water. 

So what do all these concerns equate to? At best, fires can change your water's turbidity (sediment), color, taste, and smell. However, more difficult to diagnose issues that lead to “Don't use,” “Don't drink,” and “Boil Water” notices for public health aren't out of the question after these events. Nor are cancer-causing health hazards and other dangers that have yet to be fully understood or detected.

A breakdown of the almost-immediate impact wildfires have on drinking water:

  • Changes in turbidity, color, taste, and smell.
  • Build up of ash, soil, soot, and debris.
  • Notable concentrations of sediment and heavy metals.
  • Chemicals from melted plastics, pipes, and structures.
  • Hazards from burning vegetation. 
  • Dissolved organic carbons with the potential to turn into carcinogens.
  • Chemicals that evaporate into the air and cause diarrhea, nausea, and cancer.
  • “Don't Use,” ”Don't Drink,” or “Boil Water” advisories.

Whether fires are contained or not, the future of our water can be cloudy. Let’s double-click on the lasting impact wildfires have on drinking water quality.

The Lasting Damage

Years after a fire in Colorado, land managers estimated that most of the sediment mobilized by post-fire erosion from snowmelt in the Rocky Mountains, "would likely persist" for more than 300 years. Even if anti-erosion measures, like aerial seeding and mulching, cut that time in half, that's a lasting effect that can extend over several generations. The same publication revealed that a post-fire rainstorm in Australia poured sediment into water that elevated arsenic, iron, lead, and chromium concentrations above WHO guidelines. The fallout from a severe wildfire in Northern California in 2018 uncovered water pipes containing "unsafe levels" of cancer-causing chemicals 10 months later. We share these stories to say this: Fires can affect our water for months and years, if not centuries after they've been contained. 

Our water isn't safe in the aftermath of ongoing rainfall, which flows seemingly endless sediment supplies into forested watersheds, to the runoff, erosion, and mudslides filling our cups with contaminants and debris. Burned areas are brimming with charred vegetation and piles of waste. Erosion is a recipe for almost instant pollution. Without trees, vegetation, and stable soil, rain can flush all kinds of potential hazards right into watersheds and reservoirs. Those are just some of the dangers we know of. It's reasonable to think there are more out there that haven't been detected, studied, or shared.

All of these things can impact water quality, hinder treatment processes, promote harmful algal blooms, and in severe cases, diminish the lifespan of reservoirs. Furthermore, they come with health risks that can impact everyone, from babies to seniors.

Breakdown of ongoing water quality concerns following wildfires:

  • Supplies brimming with organic carbon, heavy metals, and other contaminants.
  • Rise in soil and water chemicals like phosphate, nitrate, and nitrite. 
  • Sludge and sediment make their way into drinking water.
  • Elevation of pollutants and chemicals following rainstorms.
  • Harmful algae bloom in reservoirs.
  • Presence of cancer-causing chemicals like benzene and methylene chloride.
  • Ongoing soil erosion and water resource pollution.
  • Fluctuations in color, taste, and smell.
  • The need for secondary sources of lower-quality water.

While many of the immediate and lasting effects overlap, the long-term impact is often forgotten by the general public and left unaddressed by experts. In some cases, experts don’t even know what to look for, hindering many mitigation efforts.

Just because the fires are long gone and there are no immediate dangers or advisories doesn't mean your water is as safe as you'd like it to be.

Water Treatment is Important but Volatile

Every fire is different, as is its impact. Intensity, weather, climate, landscape, geography, topography, and more all play a part in how wildfires, directly and indirectly, affect drinking water. It's no secret that each and every fire is a learning experience. Unfortunately, we aren't always armed with the expertise to fully understand their impact on natural resources and water treatment

Even today, confusion about the effect of wildfires on drinking water is surprisingly common. Additionally, climate change, droughts, and man-made pollutants add new layers for which water managers aren't fully prepared. In short, we know the threat and are familiar with common outcomes, but given the volume of variables, we might just be scratching the surface of our understanding and ability to protect our water.

Logic tells us contaminated water supplies require treatment for us to safely drink from them. The scary truth is that mitigation via treatment plants isn't a perfect science (a quick Google search supports this claim). In fact, some would argue it's unpredictable on a good day. Additionally, "treatment" can be code for dumping more chemicals, such as disinfectants and coagulants, into your water as processes are adjusted to neutralize new, unique, and emerging hazards to public health. Either way, it's a murky outlook as water use and treatment can be unsafe during and after fires.

With our water supplies at risk and treatment untrustworthy, where do we turn? Do you drink up and hope for the best? As water filtration experts, we want to make sure you are informed, but we'll let you be the judge on what this all means. Now that we've seen what happens to our water during fire season and the years that follow, let's look at what you can do to protect yourself.

How to Protect Yourself

Wildfires are unpredictable. Your water quality shouldn't be. Your local authorities and water providers are responsible for notifying you if your water is unsafe, but that doesn't mean "safe" is safe enough. Even today, controversy is common in the aftermath of wildfires. Laws around contamination are in question, and confusion around the impact is rampant. There's reason to believe our regulators and water utility companies aren't doing enough to protect us from contaminated water. 

Your best bet is to filter your tap water before drinking or washing up. In our opinion, it can only help. An investment in a premium filtration system is an investment in your health, future, and peace of mind. Check out our full line of advanced filtration systems, complete with our cutting-edge affinity filtration technology, and start protecting your drinking water today.