ecent studies have confirmed that PVC water mains are not responsible for benzene contamination in municipal water systems following wildfire events, according to a technical brief published by the Uni-Bell PVC Pipe Association.

The brief addresses misconceptions that emerged after benzene was detected in drinking water following devastating forest fires in Santa Rosa and Paradise, California in 2017 and 2018. Some media reports incorrectly suggested PVC water mains as the source of contamination.

“This is not possible since both communities confirmed that no PVC water transmission or distribution mains were affected by the fires and remained in service throughout the events,” the report states.

According to the technical brief, the primary source of benzene in forest fires is from wood combustion, with burning homes and other structures serving as secondary sources. The report emphasizes that benzene cannot be produced from PVC combustion in an open-air fire.

While trace amounts of benzene can be released during pyrolysis — a process requiring a highly controlled environment with no oxygen present — the technical brief clarifies that pyrolysis does not occur in buried water mains during wildfires.

The most likely pathway for benzene contamination in municipal water systems after wildfires is through damaged service lines rather than from water mains. When buildings burn, service lines connecting to water mains can break, creating entry points for contaminants.

Suction in the water system used to fight the fires can draw in contaminants, the report explains. This backflow process, as defined by American Water Works Association Manual M14, can occur regardless of pipe material.

The technical brief also refutes suggestions that benzene can permeate through PVC pipes after accumulating in soil following wildfires. Citing the AWWA Water Research Foundation report Impact of Hydrocarbons on PE/PVC Pipe and Pipe Gaskets, the brief confirms that gasketed PVC pipe is highly resistant to permeation from a wide range of chemicals, including benzene.

Utilities have confirmed that PVC water transmission and distribution mains maintained their integrity during wildfire events. Both Santa Rosa and Paradise, California continue to specify and use PVC pipe after experiencing wildfires in 2018.

The U.S. National Forest Service provides further evidence of PVC pipe’s resilience by using PVC water mains for underground infrastructure in forested regions across the country — areas regularly affected by wildfires.

Source: PVC Water Mains: Not a Source of Benzene from Wildfire Events, Uni-Bell PVC Pipe Association Technical Brief, March 7, 2025.