The City’s Water Resources Department began weekly sampling in July 2018 for perfluorooctanoic acid (PFOA) and related chemical perfluorooctane sulfonic acid (PFOS) at both Lake Brandt and the entry point to the distribution system from the Mitchell Water Treatment Plant. In June 2020, the City transitioned to bi-monthly samples. 

In April 2024, the Environmental Protection Agency (EPA) finalized the National Primary Drinking Water Regulations (NPDWR), which established legally enforceable Maximum Contaminant Levels (MCLs) for six PFAS compounds in drinking water:

• PFOA and PFOS: 4 parts per trillion (ppt) each
• PFHxS, PFNA, and GenXchemicals: 10 ppt each
• PFBS: Regulated as part of a mixture

The rule also established a Hazard Index MCL of 1.0 for mixtures containing two or more of PFHxS, PFNA, HFPO-DA, and PFBS.

In 2022, the EPA's Health Advisory Level (HAL) for PFOA was 0.004 ppt and 0.02 ppt for PFOS in drinking water. In 2016 the HAL for PFOA and PFOS (individually or combined) was 70 ppt, and in 2009 it was 200 ppt.

Lake Brandt Raw Water - Mitchell Water Treatment Plant and Source Mitchell Water Treatment Plant Point of Entry

Click on the link above to see current sample results or links below image to see historical results. 

Notes:

• One part per trillion (ppt) is equal to one nanogram per liter (ng/L).
• The City’s contracted laboratory has not detected (ND) or detected values are well below the final Hazard Index values for PFNA and HFPO-DA (i.e. GenX Chemicals).