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| CDPHE PFAs Website |
On April 8, 2024 EPA announced that it had finalized a new drinking water rule within the Safe Drinking Water Act (SDWA) to address per- and polyfluorinated alkyl substances (PFAS). This has been a long journey, but now there is a definitive timeline for the state to adopt the rule, public water systems to conduct testing, and if necessary make operational changes or install treatment to comply with the newly established Maximum Contaminant Levels (MCLs). We published an Aqua Talk article on June 21, 2023 about the draft rule published in March 2023 for public comment. EPA received over 120,000 comments on the draft rule that they considered when finalizing this PFAS rule.
There are several differences between the draft and final rules, but EPA did not modify the Maximum Contaminant Level Goals (MCLGs) or the MCLs for PFOA or PFOS, which are the most common PFAS compounds detected in Colorado. PFOA and PFOS are considered carcinogens, and so the MCLGs were set at zero. This is common for drinking water contaminants. EPA is required by SDWA to set MCLs as close to MCLGs as feasible while considering benefits and costs. The final MCLs for PFOA and PFOS remained at 4.0 parts per trillion (ppt) each based on the reliability of laboratory quantification.
But EPA established more MCLGs and MCLs for individual PFAS compounds in the final rule as compared to the draft rule. Please recall that MCLGs are the maximum allowable concentration of a contaminant at which no adverse health effects are expected, with a margin of safety. Specifically, EPA added MCLGs set at 10 ppt each for PFHxS, PFNA and HFPO-DA (GenX), which are not regarded as carcinogens. The MCLs for these compounds were also set at 10 ppt each. In Colorado, we tend not to find these compounds at levels exceeding the MCLs unless the MCLs for PFOA or PFAS are exceeded. So, this change is not considered likely to be impactful to compliance status, but can impact treatment design and operations. EPA also made some changes to the hazard Index, but that is not likely to be impactful in Colorado considering the profile of PFAS compounds detected in water samples to date. So, to summarize the final MCLs are:
- PFOA and PFOS MCLs = 4.0 ppt each
- PFHxS, PFNA and HFPO-DA MCLs = 10 pt each
In terms of timing, systems are required to complete initial monitoring within three years, and then begin regular monitoring plus reporting results in the annual Consumer Confidence Reports (CCRs). However, in the final rule, the compliance deadline to meet the MCLs was extended an additional two years to allow for capital infrastructure improvements. This would also allow for two more years to complete public notice requirements for MCLs violations. The public notice tier level remained at Tier 2.
EPA kept the overall structure of the final rule consistent with the draft rule to model other chronic organic contaminants with quarterly monitoring and compliance based on a running annual average of those results. Reduced monitoring options are available, and it is possible to use prior PFAS data to meet initial monitoring requirements.
A significant need for EPA guidance on this rule remains to address treatment design and conduction pilot studies, residual waste handling and disposal, reduced monitoring and the trigger level, public notice plus communication, and much more. This is very important to foster state implementation and water system compliance. To that end, EPA recently published a draft revised guidance document for PFAS destruction and disposal for a 180-day public comment period.
The above information describes the federal minimum requirements, and states can choose to take a more stringent approach. As always, we will be engaging stakeholders in developing the PFAS rule for Colorado. The final decisions on Colorado’s PFAS rule will be made by the Water Quality Control Commission after the stakeholder process is completed.
Most systems that need to install new treatment for compliance will need to secure financial assistance. We have significant funding available now from the State Revolving Fund and Bipartisan Infrastructure Law, plus the PFAS cash fund generated by Senate Bill 2020-218. We can help water systems with testing, planning and design grants plus infrastructure funding as well. These funding sources typically have specific eligibility and grant requirements that need to be met, and our staff can help water systems navigate the process. These funding sources help with initial design and construction activities, but do not help with the long-term operating and maintenance costs. It is not certain whether all these funding sources will be available four or five years from now, so we recommend that systems move forward now with their planning for complying with the new PFAS rule.
Because we have been helping water systems address PFAS contamination for over eight years, we understand the issues and challenges. We want all systems in Colorado to gain compliance with the PFAS MCLs before the required deadline. I advise you to learn about the final PFAS rule and take steps to prepare your water system for it. If you have not yet collected PFAS samples from your system, I advise you to contact us and we will test your water for free. Getting in front of this now while funding is available is the best approach to keeping tap water safe for your customers.
Thank you.
➽ Ron Falco, P.E. Safe Drinking Water Program Manager
