Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS) Monitoring and Compliance Update
Protecting public health by providing reliable, high-quality drinking water is the top priority for the Cobb County-Marietta Water Authority (CCMWA). CCMWA continues to monitor per- and polyfluoroalkyl substances, commonly known as PFAS, and to evaluate long-term treatment and compliance needs as federal requirements evolve.
CCMWA’s drinking water continues to meet current federal and state drinking water requirements. Monitoring results collected to date remain below the federal drinking water limits established for PFOA and PFOS.
What are PFAS?
PFAS are a large group of human-made chemicals that have been used for decades in consumer, commercial, and industrial products because they resist heat, water, oil, grease, and stains. PFAS may be associated with products such as food packaging, cosmetics, non-stick cookware, stain-resistant fabrics, water-resistant materials, certain industrial processes, and some firefighting foams.
Because some PFAS break down very slowly, they can persist in the environment and are often referred to as “forever chemicals.” Preventing PFAS from entering rivers, lakes, and other source waters remains an important part of protecting drinking water supplies.
Federal drinking water regulation
On April 10, 2024, the U.S. Environmental Protection Agency (EPA) finalized the first national drinking water regulation for PFAS. The rule established enforceable Maximum Contaminant Levels (MCLs) for PFOA and PFOS at 4 parts per trillion (ppt), and for PFHxS, PFNA, and HFPO-DA (also known as GenX chemical), at 10 parts per trillion. The rule also established a Hazard Index limit of 1.0 for mixtures containing two or more of PFHxS, PFNA, HFPO-DA, and PFBS.
In May 2025, EPA announced that it would retain the PFOA and PFOS MCLs and pursue additional rulemaking related to compliance deadlines and certain other PFAS requirements. CCMWA will continue to track EPA and Georgia Environmental Protection Division guidance and comply with applicable drinking water requirements.
CCMWA monitoring
CCMWA has been proactively monitoring PFAS in its drinking water to better understand occurrence, seasonal variation, and long-term compliance needs. Under EPA’s Fifth Unregulated Contaminant Monitoring Rule (UCMR 5), public water systems across the country monitored for 29 PFAS chemicals and lithium between 2023 and 2025. CCMWA’s wholesale customers participated in UCMR 5 monitoring, and CCMWA also conducted additional PFAS monitoring at its water treatment plants.
From October 2023 through December 2024, CCMWA sampled drinking water at its water treatment plants monthly. Based on low detection frequency and concentrations below MCLs, CCMWA adjusted monitoring to every other month in 2025 and to quarterly monitoring beginning in 2026.
Current results
Results collected to date indicate that PFOA and PFOS have generally been detected in the 2 to 3 ppt range, below EPA’s MCL of 4 ppt for each compound. PFBS, one of the PFAS compounds included in the Hazard Index calculation under the 2024 rule, has been detected at very low levels. Based on CCMWA’s current results, the calculated Hazard Index has remained well below the regulatory limit of 1.0.
CCMWA will continue to evaluate PFAS data as additional monitoring results become available.
Treatment evaluation
Conventional water treatment processes are generally not designed specifically for PFAS removal. Advanced treatment technologies, including granular activated carbon, ion exchange, and certain membrane processes, can be effective for reducing PFAS, depending on water quality and the specific compounds present.
CCMWA’s granular activated carbon facility at the Wyckoff Water Treatment Plant is an example of advanced treatment technology that can help reduce PFAS. CCMWA is also working with engineering and academic partners to assess advanced treatment options for the Quarles Water Treatment Plant. This work is intended to identify treatment approaches that are effective for removing PFAS and other constituents in Quarles source water. Future phases may include design, construction, and implementation of selected treatment improvements.
CCMWA’s continued commitment
CCMWA will continue to monitor for PFAS, follow federal and state regulatory requirements, and take appropriate actions to protect drinking water quality. CCMWA also supports source-water protection efforts and policies that reduce PFAS releases into the environment before they reach drinking water sources.