Distribution System Materials and PFAS
Water distribution systems use diverse pipe materials—HDPE (high-density polyethylene), PVC (polyvinyl chloride), ductile iron, and copper—each with different PFAS-related characteristics. While most distribution pipe materials do not contain PFAS, some do contribute to PFAS exposure through leaching of fluoropolymer additives used in manufacturing or formulations.
HDPE Pipes and PFAS Leaching
High-density polyethylene pipes are widely used for water distribution, particularly in newer installations and PFAS-contaminated communities replacing lead or galvanized pipe. Studies have detected PFAS leaching from some HDPE formulations, attributed to fluoropolymer-based processing aids and stabilizers used in HDPE manufacturing. The contribution is typically small but additive to source water PFAS concentrations.
Fluoropolymer Gaskets and Joint Materials
Gaskets, O-rings, and joint sealants in water distribution systems frequently use fluoropolymer (PTFE, FKM) materials for chemical resistance and durability. These components can leach PFAS into distributed water, particularly in new installations or at elevated temperatures. NSF/ANSI Standard 61 evaluations are being updated to specifically assess PFAS extraction from these components.
Lead-Free Brass and PFAS Intersection
Lead-free brass fittings introduced after lead plumbing restrictions may contain trace PFAS from manufacturing processes. While the primary public health benefit of lead-free transitions is clear, comprehensive evaluation of replacement materials for PFAS should accompany lead removal programs to avoid introducing new chemical exposures while addressing an existing one