Per- and polyfluoroalkyl substances (PFAS)
Per- and polyfluoroalkyl substances (PFAS) are a large group of synthetic chemicals that have been widely used in consumer, commercial and industrial products for their heat, water, and oil resistant properties. They are sometimes called “forever chemicals” because they break down very slowly in the environment. PFAS have been found in water, air, and soil around the world. PFAS can enter the sources of drinking water when products containing PFAS are used or spilled onto the ground or into lakes or rivers.
According to the U.S. Environmental Protection Agency (EPA), current scientific research suggests that exposure to certain PFAS may lead to adverse health outcomes. Certain PFAS, such as PFOS and PFOA, have been largely phased out due to health concerns. Research and studies are ongoing to learn more about different PFAS including:
- Where PFAS is found in the environment
- Ways to better detect and measure PFAS
- How humans may be exposed to PFAS
- Possible health effects from PFAS exposure
- Treatment, management, and safe disposal
The U.S. EPA and the California State Water Resources Control (State Water Board) are developing drinking water standards, or Maximum Contaminant Levels (MCLs), for PFAS at extremely low concentrations to protect consumers of drinking water. MCLs are enforceable standards that include a margin of safety. In California, the State Water Board has established health-based notification and response levels which require water systems to notify the public and implement management strategies if certain PFAS are detected at or above those levels.
Management options if PFAS are found in drinking water supplies include treatment, blending different supply sources to reduce concentrations, or removing individual groundwater wells from service until they are treated. Treatment to remove PFAS includes granular activated carbon (GAC) or reverse osmosis technologies.
The U.S. EPA began requiring PFAS monitoring in drinking water under its Uncontaminated Monitoring Rule (UCMR) in 2013. In California, the State Water Board increased requirements for PFAS monitoring in 2019. Testing for PFAS in drinking water supplies is increasing through expanded requirements and voluntary monitoring.
Regional Water Supplies
The Water Authority’s drinking supplies include imported water provided through the Metropolitan Water District and seawater desalination from the Carlsbad desalination facility. Metropolitan has infrequently found PFAS at very low levels just over the detection limits in some of its supply sources. The Water Authority’s seawater desalination supplies are treated with reverse osmosis which is known to remove PFAS.
More information about the Water Authority’s supply sources can be found on the facilities page. Water quality information is also provided by local water agencies in their annual consumer confidence reports. Find your local water agency’s website.