The Effects of Wildfires on Drinking Water Quality in the Western United States, 2000-2022

Wildfires can threaten the provision of safe drinking water by altering source water characteristics or by directly damaging drinking water infrastructure. Wildfire-induced changes to source waters can disrupt normal drinking water treatment practices and are likely to present particular challenges to systems with limited operational capacity or flexibility. Effects on surface waters have lasted as long as fifteen years post-wildfire in some locations. Recent work has shown that wildfires are associated with increases in the concentrations of certain drinking water contaminants as well as the frequency of Safe Drinking Water Act violations. However, previous studies have focused on a small subset of contaminants and geographic areas over a shorter time horizon that excludes years of exceptional wildfire frequency after 2016. We study the impacts of wildfires on drinking water quality from 2000-2022 by linking a rich set of information on wildfire burn locations and severity, precise drinking water system intake locations, contaminant concentrations in drinking water, and Safe Drinking Water Act violation history in all public drinking water systems in the Western United States. Using geospatial techniques to characterize the extent of wildfire impacts to intake catchment areas, we ask how the presence of an upstream wildfire affects drinking water quality delivered by downstream public water systems at different distances and time periods post-fire. Our analysis focuses on two types of outcomes related to drinking water quality: Safe Drinking Water Act violations and drinking water contaminant concentration levels. We include a diverse set of violation types as well as numerous drinking water contaminants such as disinfectant byproducts, nutrients, volatile organic chemicals, and metals. We test for heterogeneous impacts across public water system size and source, watershed characteristics, and states. In all models, we include a set of controls for weather, temporal, and state variation. Our research builds on a growing literature aiming to better understand the impacts of climate change on public drinking water systems.

Impact/Purpose

Wildfires can threaten the provision of safe drinking water by altering source water characteristics or by directly damaging drinking water infrastructure. Wildfire-induced changes to source waters can disrupt normal drinking water treatment practices and are likely to present particular challenges to systems with limited operational capacity or flexibility. Effects on surface waters have lasted as long as fifteen years post-wildfire in some locations. Recent work has shown that wildfires are associated with increases in the concentrations of certain drinking water contaminants as well as the frequency of Safe Drinking Water Act violations. However, previous studies have focused on a small subset of contaminants and geographic areas over a shorter time horizon that excludes years of exceptional wildfire frequency after 2016. We study the impacts of wildfires on drinking water quality from 2000-2022 by linking a rich set of information on wildfire burn locations and severity, precise drinking water system intake locations, contaminant concentrations in drinking water, and Safe Drinking Water Act violation history in all public drinking water systems in the Western United States. Our analysis focuses on two types of outcomes related to drinking water quality: Safe Drinking Water Act violations and drinking water contaminant concentration levels. Our research builds on a growing literature aiming to better understand the impacts of climate change on public drinking water systems. 

Citation

Haley, B., W. Austin, C. Wachter, J. Suter, J. Burkhardt, S. Pan, B. Parthum, AND S. Kolstoe. The Effects of Wildfires on Drinking Water Quality in the Western United States, 2000-2022. American Geophysical Union Fall Meeting, Washington, DC, December 09 - 13, 2024.