Council briefed on PFAS monitoring; PFHxS detected in Well 2, staff plan follow‑up sampling

The City received a staff briefing March 26 after an internal sampling program found detectable per‑ and polyfluoroalkyl substances (PFAS) in one municipal groundwater well.

Environmental Services Manager Chris Nelson told council that the city sampled five wells over the winter to assess PFAS presence. Results showed confirmed detection of PFHxS (a PFAS compound) at Well Number 2, located near the airport. Nelson said the laboratory average for that well was about 7 parts per trillion (ppt). He noted that the State Water Board has issued non‑regulatory guidance levels that create a notification threshold (3 ppt in the State Board’s guidance) and a higher response level that would require removal from service; federal maximum contaminant levels (MCLs) for PFAS were still under development at the time of the briefing.

Nelson described the detection as a notification‑level event: the city is not operating the well in regular production while staff investigate and will perform follow‑up sampling in July. He also outlined next steps including coordination with the Groundwater Sustainability Agency and other regional partners to better determine whether the PFAS is present in the aquifer (regional source) or attributable to a nearer‑term source. Nelson emphasized that the city’s treated drinking water otherwise meets state and federal drinking‑water standards and that staff are monitoring and preparing comments to the State Water Resources Control Board as regulatory guidance evolves.

Councilmembers asked about sampling methods and whether testing directly into aquifer monitoring wells could help determine source and extent; staff said additional test wells and regional coordination would be used to refine the picture. There was no council action – the briefing was informational – but staff said they would return with follow‑up sample results and any regulatory developments.