Eliminating federal limits in drinking water on the toxic “forever chemicals” known as PFAS could end a vital safeguard against continued pollution for 18.9 million Californians.
The Environmental Protection Agency’s landmark standards for six PFAS in tap water, finalized last year, will protect tap water around the U.S. But they are under threat. Some polluters are pushing to dismantle these hard-won protections as part of a broader effort to gut environmental safeguards.
If they succeed, PFAS pollution will continue to flow from the taps of over 175 water systems across California and threaten the health of residents served by these systems.
The federal standards include first-time federal limits on the notorious forever chemicals PFOA and PFOS of 4 parts per trillion, or ppt. The agency also set limits on another three types of PFAS, in addition to a mixture of the three plus the forever chemical PFBS.
These limits are called maximum contaminant levels, or MCLs – the highest amount of a chemical legally allowed in drinking water. The standard is based on public health benefits of reducing PFAS levels, as well as the cost and feasibility of cleaning up the water.
If the EPA rolls back or weakens its standards, states could act as a backstop – if they pursue strict PFAS limits.
California has established non-enforceable response levels for just four types of forever chemicals: PFOS, PFOA, PFBS and PFHxS. The state’s response levels – the level of PFAS in tap water that can trigger cleanup actions – protect human health far less than the federal standards. They can allow some contaminants to be present up to 10 times higher than the federal standards.
Many public water systems voluntarily address PFAS contamination above the response levels. But they can choose instead simply to notify customers, without taking further action. Nothing requires the utilities to lower the amount of PFAS in the water.
California Assembly Bill 794, introduced by Assemblymember Jesse Gabriel (D-Encino), would set state PFAS drinking water standards at least as strong as federal limits, even if the agency rolls those back. If enacted, A.B. 794 would require the state water board to adopt emergency regulations and begin setting a primary drinking water standard for PFAS.
PFAS are linked to a number of serious health harms, including impaired immune system response, liver and kidney damage, hormone disruption, developmental and reproductive issues, and several types of cancer.
An estimated 177 California drinking water systems, serving over 18.9 million people, have had PFOA and PFOS at levels above 4 ppt, or have had PFHxS and PFNA above 10 ppt, between 2023 and 2025.
Without federal standards, these systems would no longer legally have to install treatment technology to remove the harmful PFAS from tap water. As a result, PFAS could continue to contaminate California’s water. Communities large and small throughout the state would be adversely affected.
Some of the largest water systems that would no longer be required to upgrade water treatment infrastructure include those serving the Los Angeles, San Diego, Orange County and Fresno regions.
Many drinking water systems across the state, including Sacramento, Riverside, Glendale, Oceanside, Atwater and Adelanto, had detected one or more of the PFAS chemicals covered by the EPA’s standard other than PFOA or PFOS above federal standards between 2023 and 2025.
If the EPA’s limits for the additional four PFAS are removed, these systems could fall through the regulatory cracks, with PFAS levels below the California response levels These systems would be able to avoid any obligation to tackle this contamination.
California systems above annual averages
The EPA standards require any drinking water systems with annual average PFAS detections above the MCL to update their systems to lower the chemical levels.
Currently, of the 177 California systems with PFAS detections, 130 systems have had annual average detections above the MCLs. They will have to continue monitoring and making adjustments to ensure they comply by the 2029 implementation date.
The new EPA standards give water utilities five years to comply. Smaller drinking water systems, defined as those serving fewer than 3,300 people, can request an extension of up to six years. In some circumstances, systems serving up to 10,000 people can also request an extension.
The EPA also established PFAS monitoring requirements for its standards, but smaller systems are not subject to monitoring as frequently as larger systems.
EWG has no way of knowing what any of the 177 systems we identified in this analysis plans are to install or upgrade treatment systems or if they have or are in the process of taking contaminated wells offline. And systems may already be treating their drinking water for PFAS in line with California’s advisory levels, even while their water tests show contamination above the EPA’s limits. In such cases, the utility might need to employ further protective measures to comply with the federal standards.
Military bases must also comply with the federal drinking water standard. Communities whose water has been contaminated by a nearby base rely on these safeguards so they can get clean water from the Department of Defense. This is often provided as bottled water, household filters, or connecting a home to a nearby municipal system.
As things now stand, California’s Camp Pendleton, which operates its own water utilities, collectively serving 56,000 service members and their families, must meet the federal limits. Scrapping the standards would mean it and other military bases in California would no longer be required to follow the federal limits.
Because the state’s response levels are non-binding, the DOD might also not address PFAS exceeding those levels. A scenario like this could jeopardize the health of service members and their families. Camp Pendleton has installed treatment systems on base but continues to detect elevated PFAS levels, according to its most recent publicly available test results, reported in February.
What’s more, 49 active and former military sites in California have already found PFAS in their groundwater or drinking water, which may in turn taint nearby private water wells.
The DOD has said it will comply with federal standards for forever chemicals in drinking water as part of its cleanup plans. A rollback of the EPA limits could prompt the department to argue it is no longer required to clean up bases to meet the 4 ppt standard.
The Pentagon might also push back on any requirement to provide clean drinking water to civilian communities in areas with PFAS contamination from nearby bases. This military response leaves the health of residents in peril.
Many sources of pollution
The flow of PFOA, PFOS, PFNA and PFHxS pollution into the state’s water systems will inevitably lead to more frequent doctor visits, cancer treatments and years of chronic illness.
At least 5,244 industrial facilities in California may be releasing PFAS into the environment, according to another EWG analysis.
Widespread PFAS contamination in the state and across the U.S. stems from the many uses of the highly toxic fluorinated chemicals in consumer and industrial products. Companies like to use these substances because of their nonstick and stain-resistant qualities.
Industrial uses aren’t the only source of PFAS pollution. Other threats to California’s drinking water supply include legacy firefighting foam containing PFAS, which was once used near military facilities and civilian airports, PFAS used in everyday products, PFAS leaching from landfills, and spreading of PFAS-contaminated wastewater sludge.
With the current state of play, polluters can continue to profit from weak regulations that enable contamination, while Californians pay the price with serious health harms. The federal PFAS standards are crucial, but they’re under threat. They must remain in place.
Every American deserves access to clean, safe water.
