Notification Level Recommendation for Perfluorohexane Sulfonic Acid (PFHxS) in Drinking Water

Mar 17, 2022

The Office of Environmental Health Hazard Assessment (OEHHA) is recommending that the State Water Resources Control Board (Water Board) establish the notification level (NL) for perfluorohexane sulfonic acid (PFHxS) at 2 parts per trillion, or the lowest level at which it can be reliably detected in drinking water using currently available and appropriate technologies. This recommendation is based on OEHHA’s development of a health-protective concentration intended to prevent noncancer effects, including thyroid, liver, and developmental toxicity.

PFHxS is a member of a large class of chemicals known as per- and polyfluoroalkyl substances (PFAS) that are used in many consumer products for their non-stick and water-, grease- and stain-resistant properties, and also in firefighting foams. Exposure to PFHxS above certain levels can cause adverse health effects, including harmful effects to a developing fetus, the thyroid, and the liver. While consumer products are a large source of exposure to these chemicals for most people, drinking water has become an increasing concern due to the persistence and tendency of these chemicals to accumulate in groundwater.

NLs are nonregulatory, health-based advisory levels that the Water Board establishes as a precautionary measure for contaminants for which regulatory standards have not been set. Certain requirements are triggered when chemicals are detected at levels that exceed their respective NLs.

For more information about PFAS, the new guidelines, NLs and the work the Water Board is doing to assess the presence of these contaminants in drinking water, please visit the Water Board’s website.