General information on PFOS/PFOA is below. Details about Cal Water’s position are available on the Leadership on PFAS page.

Common names for PFOS are perfluoroctanesulfonic acid and perfluoroctylsulfonic acid. Some common PFOA names include perfluorocaprylic acid, perfluoroctanoic acid, and perfluoroheptanecarboxylic acid. PFOS and PFOA are manmade compounds that have been used to make carpets, clothing, fabrics for furniture, paper packaging for food, and other materials (e.g., cookware) that are resistant to water, grease, or stains. They are also used for firefighting at airfields and in a number of industrial processes.

Protecting our customers’ health and safety is our highest priority, and Cal Water is committed to complying with all standards set by the public health experts. Although PFOS and PFOA do not have maximum contaminant levels (MCL), knowing that these are constituents of emerging concern, Cal Water has already tested for the presence of PFOS and PFOA in all of its active sources. Although it is not required by the state, we believe it is the right thing to do.

In the smaller number of cases across the state where detection levels were above the levels at which state public health experts have recommended water suppliers take action (the response level), we took the affected sources out of service to safeguard customers. We have installed treatment on some sources and are working through our plan to install treatment at other key sources to enable us to return those sources to service, so that we can ensure long-term reliability of a safe, clean water supply.

Studies indicate that long-term exposure to PFOS and PFOA over certain levels could have adverse health effects, including developmental effects to fetuses during pregnancy or breastfed infants; cancer; or liver, immunity, thyroid, and other effects. Potential health impacts related to PFAS compounds from all sources (which also include food wrappers, firefighting foam, and non-stick cookware, for example) are still being studied, and research is still evolving on this issue. As such, we will continue development of an MCL for PFOS and PFOA at the state and federal level, and will comply with any regulations eventually set.

This does shed light on the importance of protecting our water resources. While we are doing our part to treat the water and meet the standards the public health experts have set, it’s important that our population as a whole focuses on being good stewards of the environment and takes steps to prevent impacting the water supply.

Additionally, we believe a comprehensive approach is needed to properly address the situation.  We’ve encouraged the EPA to establish a consistent, science-based standard as quickly as feasible, and strongly supported state legislation that will prohibit the sale and use of certain products that contain PFAS (Senate Bill 1044) and require the certification of accurate testing methods for PFAS (Senate Bill 1056). We have also filed a lawsuit to hold the manufacturers of the compounds responsible and prevent our customers from having to bear the costs of treatment. 

More information on PFOS and PFOA is available at: