Assessing Water Quality Impacts of Wildfire-Induced Depressurization in Water Systems: an Experimental Method

Abstract In the past decade, communities have detected volatile organic compounds (VOCs) in their water distribution systems following wildfire impacts (e.g. system damage and depressurization). This study outlines a comprehensive experimental framework developed to quantify the effects of localized water system depressurization (e.g. loss of pressure at a house) as a mechanism for VOC contamination in water systems following wildfire events. The methodology employs a modular, instrumented vacuum test setup connected to a compartment with a consistent, well-characterized fuel load. The modular design facilitates targeted experimentation, enabling researchers to assess specific parameters influencing VOC contamination during local depressurization. The integration of sensors and video imagery enables researchers to quantify results within specific fire exposures and depressurization conditions. The integrated sensors and imagery allows for conditions—such as temperature, airflow rate, and material deformations—to be continuously monitored. Proposed sampling protocols provide methods for post-test sampling to quantify total system exposure to VOCs from the burning compartment and the response of the system components to that exposure, such as the levels of VOCs leached from pipes post-exposure and how system recovery techniques may influence concentrations of VOCs leached. Though these methods are presented in the context of VOC contamination from localized depressurization, the framework can be adapted to investigate other water system concerns following pressure loss, such as pathogens, turbidity, and heavy metals. The presented methodology provides a preliminary framework for assessing depressurization-induced contamination and the effectiveness of recovery strategies in fire-affected water systems.