EPA announces new regulations for Public Water Systems  

On April 10, 2024, the U.S. Environmental Protection Agency (EPA) announced a rule setting enforceable maximum contaminant levels (MCLs) in drinking water for five per- and polyfluoroalkyl substances, also known as PFAS. The EPA concluded that there is no level of exposure for two of the compounds, PFOS and PFOA, without risk of harm to human health. The EPA set MCLs for these compounds at the lowest levels current technology can detect and set MCLs for three other compounds at similarly low thresholds. This memorandum provides an overview of the rule as it relates to the City of Dallas water system and results from the city’s water sampling program.   

As a reminder, PFAS are a group of synthetic chemicals used in a wide variety of consumer products and industrial applications such as: firefighting foam, non-stick metal coating for cookware, paper food packaging, creams and cosmetics, textiles for furniture and outdoor clothing, paints and photography, pesticides, chrome plating, and pharmaceuticals. Even though some PFAS compounds have been largely phased out due to health and environmental concerns, numerous PFAS are still in use today. 

The new PFAS regulation sets individual MCLs under the Safe Drinking Water Act (SDWA) for five PFAS compounds shown in the chart below (PFOA, PFOS, PFHxS, PFNA, and HFPO-DA), and a Hazard Index MCL for drinking water containing mixtures of two or more of PFHxS, PFNA, HFPO-DA, and PFBS. The Hazard Index accounts for the combined health risks from mixtures of PFAS. 

Additionally, the new EPA regulation requires all Public Water Systems (PWS) which includes Dallas, to complete initial monitoring to establish a baseline by 2027, followed by ongoing compliance monitoring and implementation of solutions, if necessary, to reduce PFAS by 2029. Beginning in 2029, PWS that have PFAS in drinking water at levels which violate one or more of these MCLs, based on an annual running average, must take action to reduce the levels in their drinking water. All PWS will be required to make the results available to the public. 

EPA uses the Unregulated Contaminant Monitoring Rule (UCMR) to collect data for suspected contaminants in drinking water to support future regulatory determinations to protect public health. The fifth and current monitoring cycle, UCMR5, required utilities to monitor for 30 contaminants (29 PFAS compounds and lithium) between 2023 and 2025. 

Dallas Water Utilities (DWU) has completed the UCMR5 sampling effort, collecting water from each of our three water treatment plants (WTP): Eastside WTP, Bachman WTP and Elm Fork WTP. DWU began monitoring for PFAS under UCMR5 in March 2023 and has completed the UCMR5 monitoring requirement. The results indicate that the expected levels for PFAS in DWU’s drinking water will comply with the new regulatory limits at this time.   

DWU is preparing to include the PFAS results in this year’s Consumer Confidence Report well in advance of the required regulatory timeline of 2027. The table below highlights the results of the sampling program:  

In addition to complying with UCMR5, DWU is proactively incorporating PFAS monitoring into the source water sampling program, investigating possible PFAS sources to mitigate potential exposure, evaluating established and emerging treatment technologies, and researching near- and long-term strategies to reduce PFAS levels.  

DWU is committed to providing ongoing superior rated drinking water services. DWU’s tap water meets all established regulatory requirements for drinking water and our system is rated as a Superior Water System, the highest rating offered by the Texas Commission on Environmental Quality.   

Over the next three years, DWU will continue PFAS monitoring for the targeted five individual compounds and the substances included in the Hazard Index as required by EPA. DWU will continue to comply with all current regulations that apply to its drinking water and will comply with all future regulations as well.