PFAS: Per- and Polyfluoroalkyl Substances Drinking Water Systems (2024)

Per- and polyfluoroalkyl substances (PFAS) are a group of more than 12,000 human-made substances that are not naturally occurring and are resistant to heat, water, and oil. These chemicals have been used and produced extensively in the United States for both commercial and industrial purposes, as well as for emergency fire response. Due to their unique chemistry, PFAS have been widely used as surface coatings and protectant formulations in consumer goods such as carpet and home textiles; clothing; food packaging; and non-stick cookware. PFAS have also been used as a surfactant in chrome plating, firefighting foam, and other industrial applications. In typical conditions, PFAS are resistant to degradation and do not break down in the environment. These substances can accumulate within the human body and are toxic at relatively low concentrations.

Perfluorooctanoic acid (PFOA) and Perfluorooctane sulfonic acid (PFOS) are two types of PFAS that are no longer manufactured of imported into the US, though there could be some imported goods that contain these substances. Other PFAS-containing goods and materials are still being produced and used in the US. Exposure to unsafe levels of PFOA and PFOS may result in adverse health effects including developmental effects to fetuses during pregnancy, cancer, liver effects, immune effects, thyroid effects, and other effects (such as cholesterol changes). PFOA and PFOS have been found in the blood of nearly all people tested across several national studies. According to the Centers for Disease Control and Prevention (CDC), levels of both PFOA and PFOS have steadily decreased in the US since 1999-2000.

Exposure and Occurrence

In the environment, PFAS has been detected in air, water, wastewater, and soil worldwide. PFAS are especially present in and around manufacturing facilities. Some PFAS are volatile and can be carried long distances through the air. This can lead to contamination of soils and groundwater far from the emission source. PFAS have been detected in many parts of the world, including oceans and the Arctic, indicating that long-range transport is possible.

People are typically exposed to PFAS through food, food packaging, consumer products, house dust, and drinking water. Four major sources of PFAS in drinking water are fire training and response sites; industrial sites; landfills; and wastewater treatment plants and biosolids. Exposure through drinking water is a concern, as once in groundwater, PFAS are easily transported large distances, tend to accumulate in groundwater, and can contaminate drinking water wells and other sources of drinking water, including lakes and rivers. Source water contamination is typically localized and associated with a specific use or activity regarding PFAS. Contaminated drinking water has led to high levels of exposure to PFAS for some populations residing near manufacturing facilities that use or have used PFAS in their manufacturing process.

More information about PFAS in non-drinking water, maps, and other actions in California addressing PFAS can be found at the State Water Board’s PFAS web portal.

PFAS Regulations for California Drinking Water

Public Health Goals and Maximum Contaminant Levels

On March 14, 2023, the US EPA announced proposed national primary drinking water maximum contaminant levels (MCLs) for six PFAS: PFOA and PFOS as individual contaminants, and PFHxS, PFNA, PFBS, and GenX as a PFAS mixture. The regulation proposed by US EPA would require public water systems to monitor for these PFAS, notify the public of the levels of these PFAS, and reduce the levels of these PFAS in drinking water if they exceed the proposed MCLs. As of March 2023, MCLs for PFAS in California have not yet been established. The development of standards for PFOA, PFOS, and other PFAS are among the priorities of the Division of Drinking Water. Any updates to the upcoming rulemaking process for PFOA and PFOS in California will be posted at the PFOS and PFOA MCL rulemaking record.

The Division of Drinking Water has requested that the Office of Environmental Health and Hazard Assessment (OEHHA) develop Public Health Goals (PHGs) for several PFAS. On July 22, 2021, OEHHA released draft PHGs for two PFAS: PFOA and PFOS. PHGs are established by OEHHA and are concentration of drinking water contaminants that pose no significant health risk, based on current risk assessment principles, practices, and methods. OEHHA establishes PHGs pursuant to HSC §116365(c) for contaminants with MCLs, and for those for which MCLs will be adopted. HSC §116365(a) requires a contaminant’s MCL to be established at a level as close to its' PHG as is technologically and economically feasible, placing primary emphasis on the protection of public health. In this way, PHGs serve as the basis for the development of MCLs. As of August 2022, there are no established PHGs for PFAS, though several are in development. The Division of Drinking Water has also requested that OEHHA include evaluations as to whether PFAS can be grouped together for regulatory purposes or based on specific characteristics or features of the chemicals.

The US EPA has released interim lifetime health advisories (LHAs) for PFOA and PFOS. These interim LHAs supersede the pervious LHAs that the US EPA released for PFOA and PFOS. In addition, US EPA has released final LHAs for two other PFAS: perfluorobutane sulfonic acid (PFBS) and hexafluoropropylene oxide dimer acid and its ammonium salts (GenX). Similar to PHGs, LHAs are developed by the EPA and identify the concentration of a contaminant in drinking water at which adverse health effects are not anticipated to occur over a lifetime. The State of California does not use LHAs as the basis for developing MCLs. However, the State Water Board and the Division of Drinking Water are closely monitoring EPA actions addressing PFAS.

Notification and Response Levels

Notification levels (NLs) are nonregulatory, health-based advisory levels established for contaminants in drinking water for which maximum contaminant levels have not been established. Notification levels are established as precautionary measures for contaminants that may be considered candidates for establishment of maximum contaminant levels but have not yet undergone or completed the regulatory standard setting process prescribed for the development of maximum contaminant levels and are not drinking water standards. They represent the concentration level of a contaminant in drinking water that does not pose a significant health risk but warrants notification. Notification levels are issued by the Division of Drinking Water and developed based on recommendations made by the OEHHA.

A response level (RL) is set higher than a notification level and represents a recommended chemical concentration level at which water systems consider taking a water source out of service or provide treatment if that option is available to them. Starting in January 2020, water systems that receive an order and detect levels of PFAS substances that exceed their response level, shall take a water source out of use, treat the water delivered, or provide public notification.

When chemicals are found at concentrations greater than their notification and/or response levels, certain requirements and recommendations apply. Statutory requirements for public notification are contained in section 116455 of the Health and Safety Code (HSC §116455). PFAS with notification and response levels have additional requirements per HSC §116378. Further information can be found at the Notification and Response Levels webpage. Below is a summary of PFAS notification and response levels issued, requested, or proposed.

PFAS Monitoring and Results for Drinking Water

Fifth Unregulated Contaminant Monitoring Rule (UCMR5)

On December 27, 2021, the United States Environmental Protection Agency (US EPA) published UCMR5 to Title 40 of the Federal Register (40 CFR, Part 141). UCMR5 requires public water systems to perform sample collection and analysis for 30 chemical contaminants between January 2023 and December 2025, including 29 PFAS and lithium. The goal of UCMR5 is to provide scientifically valid data on the national occurrence of these contaminants in drinking water. All public water systems serving more than 10,000 people (i.e., large systems) will monitor; all public water systems serving 3,300 to 10,000 people; and a representative sample of 800 randomly selected public water systems serving fewer than 3,300 people will monitor pursuant to UCMR5. As US EPA finalizes its sampling design plan for each sample collection year, US EPA will notify the participating small systems. US EPA is responsible for all analytical costs associated with UCMR5 compliance at systems serving fewer than 10,000 people.

Sample analysis is required to be performed by laboratories approved by US EPA for UCMR5. A list of laboratories approved for UCMR5 can be found on US EPA’s website. The analytical methods to be used for UCMR5 PFAS analysis are EPA Method 533 and EPA Method 537.1. UCMR5 contains all 29 PFAS that are within the scope of EPA Method 533 and EPA Method 537.1.

Sample collection and analysis will begin in January 2023. US EPA anticipates posting the first set of preliminary UCMR5 results in mid-2023 and expects to update the results appropriately quarterly thereafter. When available, data collected for UCMR5 will be hosted at the UCMR Occurrence Data Webpage on US EPA’s website. All systems that monitor under UCMR5 are required to notify their customers of the availability of UCMR5 results no later than 12 months after results are known. Community water systems are also required to report UCMR5 results at or above the minimum reporting level in their annual Consumer Confidence Report (CCR). For more information regarding UCMR5 including an overview fact sheet, the list of contaminants, minimum reporting levels, rule text, reporting requirements: US EPA’s UCMR5 Webpage.

Division of Drinking Water General Monitoring Orders

Assembly Bill 756 (2019-Garcia), approved by the Governor on July 31, 2019, and codified as Health and Safety Code section 116378 (HSC §116378), authorizes the State Water Board to issue orders requiring public water systems to monitor for PFAS. Since 2020, the Division of Drinking water has issued several general monitoring orders to public water systems in California. It is required by HSC §116378 that if monitoring results in a confirmed detection, then a water system must report that detection in the annual Consumer Confidence Report (CCR). Additional requirements and information regarding PFAS general orders issued by the Division of Drinking water can be found at the PFAS DDW General Order webpage.

On October 31, 2022, The Division of Drinking Water issued General Order DW-2022-0001-DDW pursuant to HSC §116378 for the monitoring of 25 PFAS at drinking water system sources that are at risk for potential contamination by PFAS due to proximity with other water sources known to have confirmed PFAS detections. The order was issued for 1,296 sources belonging to 384 public water systems. Sample collection and analysis is to be conducted quarterly, beginning with the first calendar quarter of 2023, and continuing until further notice. Sample analysis is to be performed using EPA Method 533. Public water systems ordered to monitor under DW-2022-0001-DDW received or will receive direct communication regarding their compliance. No action is required of public water systems that did not receive direct communication regarding the order or were not named in the order. More information including order text, list of systems/sources for monitoring, and analyte list can be found at thePFAS DDW General Orderwebpage.

The Division of Drinking Water has issued PFAS General Monitoring Orders on two previous occasions. The monitoring for those orders is complete, and the orders have since been rescinded. On February 16, 2021, the Division of Drinking Water issuedGeneral Order DW-2021-0001-DDWpursuant to HSC §116378 for the testing of 18 PFAS on and in the vicinity of United States Department of Defense sites. The order was sent to 150 public water systems with 356 wells, combined. Sample collection and analysis were to be conducted quarterly for four subsequent quarters starting on or before June 30, 2021. Sample analysis was to be performed using EPA Method 537.1. Public water systems ordered to monitor under DW-2021-0001-DDW received direct communication regarding their compliance. No action is required of public water systems that did not receive direct communication regarding the order or were not named in the order. More information including order text, list of systems/wells for monitoring, and analyte list can be found at thePFAS DDW General Orderwebpage.

On August 27, 2020, the Division of Drinking Water issuedGeneral Order DW-2020-0003-DDWpursuant to HSC §116378 for the testing of 18 PFAS to expand on the detected result from previous monitoring of PFAS ordered in 2019. The order was sent to 224 public water systems with 887 wells, combined. Sample collection and analysis were to be conducted quarterly for four subsequent quarters starting on or before December 31, 2021. Sample analysis was to be performed using EPA Method 537.1. Public water systems ordered to monitor under DW-2021-0003-DDW received direct communication regarding their compliance. No action is required of public water systems that did not receive direct communication regarding the order or were not named in the order. More information including order text, lists of systems/wells for monitoring, and analyte lists for these orders can be found at thePFAS DDW General Orderwebpage.

On March 2019, the Division of Drinking Water issued HSC §116400 Orders to 600 water system sites. Nearly 250 locations in the vicinity of airports with fire training and response areas, and municipal solid waste landfills are being reported to the State Water Boards for four consecutive quarters. Resulting dataset of this monitoring can be found at this file: pfas_monitoring_Q1Q2Q3Q4.xlsx.

Third Unregulated Contaminant Monitoring Rule (UCMR3)

On May 2, 2012, US EPA published UCMR3 to the Federal Register (40 CFR, Parts 141 and 142). UCMR3 required the sample collection and analysis of 30 drinking water contaminants, six of which were PFAS, between January 2013 and December 2015. All public water systems serving more than 10,000 people and a representative sample of 800 public water systems serving 10,000 or fewer people were subject to monitoring for 21 List 1 contaminants, including the 6 PFAS contaminates, pursuant to UCMR3. Sample analysis was conducted using EPA Method 537, Rev. 1.1 by EPA approved laboratories. At that time, the lowest concentration minimum reporting levels established by US EPA for PFOS and PFOA were 6.5 ng/L and 5.1 ng/L, respectively.

Monitoring under UCMR3 is complete and all results have been published. No action regarding UCMR3 is required of public water systems at this time. The resulting data is hosted at the UCMR Occurrence Data Webpage on US EPA’s website. A summary of UCMR3 results for PFOA PFOS and PFOA in California can be found at this file: UCMR3_CA_Summary_Data_for_PFOS_and_PFOA.xlsx

For more information regarding UCMR3 including an overview fact sheet, the list of contaminants, minimum reporting levels, rule text, reporting requirements: US EPA’s UCMR3 Webpage.