Understanding PFAS
On March 15, 2019, the State Water Resources Control Board (SWRCB) ordered water agencies throughout California to test drinking water wells for a group of chemicals known as PFAS over the course of four quarters (12 months). Since then, PFAS regulations have continued to evolve to ensure public health is adequately protected.
What are PFAS?
PFAS, short for per- and polyfluoroalkyl substances, are a large group of manufactured substances that do not occur naturally in the environment and are resistant to heat, water, and oil. Since the 1940s, PFAS have been used in a wide range of industrial and everyday consumer products, such as surface coating for carpets and upholstery, food packaging, nonstick cookware, and fire-fighting foams. Due to their widespread use and near indestructability, PFAS have been detected in both the environment and in blood samples of individuals tested.
These substances are persistent in the environment, can accumulate within the human body over time, and are toxic at relatively low concentrations.
Notably, Perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), two specific types of PFAS, are no longer manufactured or imported into the United States; however, there could be some imported goods containing trace amounts of these substances remaining in the U.S.
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).
How does PFAS get into drinking water?
Major sources of PFAS include firefighting foams used at training and emergency response sites, industrial and manufacturing sites, landfills, and wastewater treatment plants. PFAS can enter drinking water supplies when products containing them are applied or spilled onto the ground, or wash into lakes and rivers. Once in groundwater, PFAS can easily travel long distances and can contaminate both soil and drinking water sources. PFAS can also be released in the air, ultimately finding their way into rivers and lakes that serve as sources of drinking water.
What are Notification & Response Levels, and Public Health Goals?
Notification Level - A specific concentration of a contaminant in drinking water delivered for human consumption that the Division of Drinking Water (DDW) has determined, based on available scientific information, does not pose a significant health risk but warrants notification pursuant to the California Health & Safety Code section 116455. Notification Levels are non-regulatory, health-based advisory levels established by DDW when there is no maximum contaminant level (MCL) established.
Response Level - A specific concentration of a contaminant in drinking water delivered for human consumption, at which the DDW recommends taking additional steps, beyond a Notification Level, to reduce exposure to the contaminant. Response Levels are non-regulatory, health-based advisory levels established by DDW when there is no MCL. The established Response Levels for regulated PFAS chemicals are shown below in Table 1.
Public Health Goal - A public health goal (PHG) is a specific concentration of a contaminant in drinking water that is considered protective of public health. A PHG reflects the risk from long-term exposure to a contaminant and should not be used to estimate risks from short-term or acute exposure. Developed by the Office of Environmental Health Hazard Assessment (OEHHA), PHGs are not regulatory requirements, but instead represent non-mandatory goals. On April 5, 2024, OEHHA adopted PHGs for two PFAS compounds: PFOA at 0.007 ng/L (ppt) and PFOS at 1 ng/L (ppt).
Maximum Contaminant Level
Maximum contaminant level (MCL) is a health protective drinking water standard to be met by public water systems. MCLs take into account the chemical's health risks, ability for detectability and treatability, as well as costs of treatment. Health & Safety Code §116365(a) requires a contaminant's MCL to be established at a specific concentration as close to its PHG as is technologically and economically feasible, placing primary emphasis on the protection of public health. The MCL is the regulated and enforceable level that water suppliers must not exceed.
PFAS New Notification Levels
On February 6, 2020, the SWRCB announced it is lowering the notification levels for two PFAS compounds: PFOA and PFOS. Following this announcement, the SWRCB established NLs and RLs for two more PFAS compounds: PFBS and PFHxS. As shown in Table 1, the current notification levels and response levels are provided below along with their date of issuance. A ppt is the equivalent of four grains of sugar dissolved in an Olympic-sized swimming pool.
Table 1. State of California PFOS/PFOA Notification and Response Levels
| Abbreviation | Chemical name | Notification Level (ng/L or ppt) | Response Level (ng/L or ppt) | Date Issued |
|---|---|---|---|---|
| PFOA | Perfluorooctanoic acid | 5.1 | 10 | February 6, 2020 |
| PFOS | Perfluorooctane sulfonic acid | 6.5 | 40 | February 6, 2020 |
| PFBS | Perfluorobutane sulfonic acid | 500 | 5,000 | March 5, 2021 |
| PFHxS | Perfluorohexane sulfonic acid | 3 | 20 | October 31, 2022 |
PFAS New Maximum Contaminant Level
On April 10, 2024, the EPA established MCLs for 6 PFAS. As shown in Table 2, these MCLs are based on a Running Annual Average (RAA) and include individual MCLs for PFOA, PFOS, PFHxS, PFNA, and HFPO-DA, as well as a Hazard Index MCL for PFAS mixtures containing at least two or more of PFHxS, PFNA, HFPO-DA, and PFBS. The SWRCB has 2 years to adopt these Federal MCLs or propose a stricter requirement for California water systems to follow. As of now, RPU along with all Public Water Systems are in the initial monitoring phase in preparation for the 5-year deadline (2029) to reduce PFAS levels and comply with EPA’s final MCLs.
Table 2. EPA PFAS Maximum Contaminant Levels
| Compound | Final MCLG | Final MCL (enforceable levels) |
|---|---|---|
| PFOA | Zero | 4.0 ppt |
| PFOS | Zero | 4.0 ppt |
| PFHxS | 10 ppt | 10 ppt |
| PFNA | 10 ppt | 10 ppt |
| HFPO-DA (GenX Chemicals) | 10 ppt | 10 ppt |
| Mixtures (PFHxS, PFNA, HFPO-DA, PFBS) | 1 (unitless) | Hazard Index 1 |
Should I be concerned about RPU’s water?
RPU closely monitors any water distributed to its customers and has complied with all new drinking water PFAS regulations. RPU will continue to monitor for PFAS and will report the data to the public in the annual Water Quality Report that will be published by July 1st for the previous calendar year at www.RiversidePublicUtilities.com/WQR.
RPU management and staff continue to engage with the SWRCB regarding any future PFAS regulatory changes to remain at the forefront of any developed regulations.
More information on PFAS
More information on PFAS is available from the California State Water Resources Control Board (SWRCB): http://www.waterboards.ca.gov/pfas/ and the U.S. Environmental Protection Agency (EPA): www.epa.gov/pfas/. For additional questions, contact RPU water system representatives at (951) 826-5647 or our Customer Call Center at (951) 826-5311.