The extent and intensity of wildfires have increased over the past few decades, according to “Impacts of Wildfires on Highway Assets,” an April 2026 study published by the Federal Highway Administration. It reports that the resulting damage to underground drainage infrastructure has been extensive, leading to significant costs.
Wildfires can have devastating effects on certain types of pipelines, the study asserts, making it vital to choose wisely. When comparing pipe materials, concrete protects against wildfires better than plastic or metal, according to the FHWA, which states that it has “Generally higher fire resistance than other material types.” Concrete is a poor conductor of heat, unlike PVC and HDPE, which are prone to melting, and corrugated steel pipe, which usually has a flammable coating.
Concrete pipe serves as both a conduit and a structure, supporting the ground and anything else that sits on top of it. When plastic or metal pipeline melts or buckles, not only is the pipeline lost, it also risks collapsing any roads, highways, and other pavement on the surface above. The study reports that plastic and metal pipeline failures have severely limited fire response and evacuation attempts during a crisis and recovery efforts in its aftermath.
A secondary but potentially more dangerous threat from wildfires, according to the study, is the risk of post-fire flooding. Extreme heat causes decreased soil infiltration capacity and stability, decreased vegetation, and possible hydrophobic layers, making fire damaged terrain susceptible to floods. Lighter pipeline materials such as plastic and metal can be displaced by fast-moving flood waters, but the weight of concrete pipe helps it resist floatation. Plus, flooding and fire-related debris may cause clogging and additional damage to less durable PVC, HDPE and corrugated steel drainage systems.
Reliable, resilient concrete pipes are essential following a wildfire, and the study also emphasizes the importance of fire-resistant concrete culverts, which are particularly vital for dealing with post-fire flooding and debris flow. The study cites an interview with the town manager of Paradise, California, following the notorious Camp Fire of 2023. He reported that the Town of Paradise has replaced all of its HDPE culverts with concrete following the disaster.
Download a copy of “Impacts of Wildfires on Highway Assets”:
https://highways.dot.gov/sites/fhwa.dot.gov/files/FHWA-HRT-26-005.pdf
Fire resistance should be a priority for any drainage system, even in areas that aren’t prone to wildfires. Plastic and metal pipe is vulnerable to fire damage from accidents, threatening both the drainage system and any roadway above it. Concrete, however, is resistant to fire, rot, and corrosion, and will endure decades of weather and wear.
Learn more about fire-resistant precast concrete pipe, culverts, inlets, catch basins, and other underground infrastructure:
https://www.countymaterials.com/pipe-and-underground-infrastructure
View County Materials’ Reinforced Concrete Pipe brochure:
https://www.countymaterials.com/hubfs/downloads/2023_RCP_Brochure_En_1200877929.pdf