PFAS Rule Updates: Extended Deadlines and What They Mean for Colorado Water Systems

The EPA is proposing revisions to the federal PFAS Drinking Water Rule, introducing significant changes that will provide Colorado drinking water systems with more flexibility and time to meet compliance standards. Here is what public water systems need to know about the upcoming changes and how the department is responding to keep Colorado aligned with federal standards.

What is changing for water systems?

Originally, the PFAS Rule required systems to comply with new maximum contaminant levels (MCLs) for six chemicals and a Hazard Index by April 1, 2029. Under the EPA’s proposed revisions announced in May 2026:

• Four chemicals and the Hazard Index may be dropped: The EPA plans to rescind the regulatory requirements for PFHxS, PFNA, HFPO-DA, PFBS, and the Hazard Index mixture.
• More time for PFOA and PFOS: The EPA is proposing a modified exemption process to give eligible water systems up to two additional years to meet PFOA and PFOS MCL requirements, pushing the compliance deadline to 2031. This extension framework is largely driven by the significant capital costs, supply chain constraints, and workforce limitations systems face when designing and installing new treatment facilities.
• Interim measures and public notice: An exemption gives systems more time, but requirements during that extension period are dependent on a system's specific PFOA or PFOS levels: 
• 12 parts per trillion (ppt) and above: If a system’s PFOA or PFOS levels equal or exceed 12 ppt, they must implement at least two interim control measures. These can include public education efforts and operational adjustments, like blending water sources, or providing point-of-use solutions directly to consumers, such as certified pitcher filters.
• Between 4 ppt and less than 12 ppt: If a system's PFOA or PFOS levels are above 4 ppt and less than 12 ppt, the proposed framework does not require them to implement interim control measures during the exemption period.
• Regardless of contamination levels, all exempted systems will be subject to public notice requirements to ensure their communities remain informed while long-term treatment solutions are built.

(Note: Without an approved exemption, suppliers will still be required to meet the original April 1, 2029 deadline).

What is the department doing?

Because the EPA signaled that these revisions would occur after the deadline for states to submit primacy applications, the EPA strongly encouraged states to request an extension. The department officially requested a six-month primacy extension this spring. This is an administrative step that provides us with the necessary time to review the EPA’s proposed changes and ensure Colorado’s exemption process aligns with the new federal framework. This extension does not impact public drinking water systems or alter the department’s enforcement oversight. It simply ensures our regulatory authority remains intact before the federal rule takes full effect in April 2027.

What are the next steps?

We will continue to update systems as the EPA finalizes these revisions. Currently, the department is communicating directly with the EPA regarding these drafts and the practical feasibility of implementing these PFAS exemptions at the state level.

Importantly, the proposed extensions and revisions do not change immediate testing deadlines. Suppliers must still comply with the initial monitoring requirements for the six PFAS chemicals by April 1, 2027. To satisfy this requirement, systems must complete monitoring and report the results of either two or four samples (depending on system size and source water type) per entry point. If a supplier has completed all required initial monitoring, they should check their monitoring schedule and AIMS Tool to ensure initial monitoring results have been accepted and marked complete. 

For more information, visit the department’s PFAS rule webpage, sign up for future PFAS Rule email notifications, or email cdphe_wqcd_DWrules@state.co.us.

➽ Bryan Pilson Technical, Regulatory Implementation and Coordination Unit Manager

Colorado Adopts Federal PFAS Rule

Resources: 

• Frequently asked questions on PFAS Initial Monitoring 
• PFAS in Finished Drinking Water for PWS interactive and dynamic map 

The State of Colorado’s Water Quality Control Commission recently took final action in August 2025 and has adopted the April 2024 EPA PFAS National Primary Drinking Water Regulation into the Colorado Primary Drinking Water Regulations (Regulation 11). EPA has indicated that they plan to make changes to this rule and finalize them in 2026.  Colorado’s PFAS Rule will adjust to these changes, but remain at least as stringent as the federal rule to maintain program primacy. However, no changes are expected to the initial monitoring rule’s timeline. Many drinking water systems have already started these efforts. For the PFAS rule, all community and non-transient, non-community water systems are required to complete initial monitoring for PFAS in all entry points by April 1, 2027.

This is a public health protection measure to facilitate positive public health outcomes (and environmental protection) in Colorado and the nation. This class of omnipresent chemicals and their serious effects on human health have been recently addressed with this regulation, both in drinking water and PFAS reductions in source waters. Thanks to the new PFAS regulations, this class of chemicals can be monitored and public exposure issues addressed. 

The Water Quality Control Division (WQCD) wants to help water systems start sampling for per- and poly-fluoroalkyl substances (PFAS) now, reducing the sampling demand as systems prepare for this upcoming deadline. To this end, WQCD has been reaching out to systems that have yet to start PFAS sampling to notify them that we are offering to fund one-time sampling through the PFAS Grant Program. The deadline to apply for this free sampling opportunity is January 9, 2026. After this deadline passes, funding for one-time sampling will no longer be available, and systems will need to contact a certified lab and complete the sampling requirements as required under the regulation at their own expense.

The current six regulated PFAS chemicals and their respective Maximum Contaminant Levels (MCLs) include:

• PFOA - 4.0 ppt
• PFOS - 4.0 ppt
• PFHxS - 10 ppt
• PFNA - 10 ppt
• HFPO-DA (GENX) - 10 ppt
• Mixture of two or more: PFNA, PFHxS, GenX, and PFBS - Hazard Index of 1.0

Sampling results from initial monitoring will be used to determine the future compliance monitoring schedule for each system. If PFAS results are found to exceed the current MCLs, completing initial monitoring will also allow systems to fully understand their PFAS system issues and begin the appropriate planning to address the contamination. If treatment is necessary, funds like the PFAS Grant Program, the Emerging Contaminants in Small or Disadvantaged Communities Grant Program (EC-SDC Grant Program), and the State Revolving Fund are available to assist systems.

Unfortunately, some drinking water wells in remote rural areas have been shown to be vulnerable to PFAS contamination due to a variety of potential sources such as fire fighting foams, individual sewage disposal systems (ISDS), biosolids applications on farm fields, various industries, and landfills. PFAS compounds are pervasive in the environment, and early sampling can provide more opportunities for funding support. Fortunately, PFAS in drinking water is treatable, and the Division is here to assist public water systems and communities with technical and financial support.

➽ Adam J. Taubman Emerging Contaminants Coordinator 

➽ Claire Wadler PFAS Program Specialist

PFAS Grant Program Over the Past 5 Years

Click here for more information about the PFAS Grant Program.

PFAS are man-made chemicals with unique properties that make them useful for many consumer and industrial uses (e.g., waterproofing, non-stick surfaces). But those properties also make them persistent in the environment. PFAS chemicals from firefighting foam, personal products, and other substances are toxic and may get into the groundwater and surface water, potentially contaminating Colorado’s drinking water supplies. There is evidence that exposure to PFAS can lead to adverse human health effects including low infant birth weights, cancer and negative effects on the immune system. 

The state continues to address PFAS issues through legislative-directed funding from Senate Bill 20-218. The Colorado Department of Public Health and Environment Hazardous Substances Response Act (SB20-218) was signed into law on June 29, 2020 ( C.R.S. 8-20-206.5(7)). 

The act created fees on the transportation of fuel products, which will be collected between September 1, 2020, and September 30, 2031, when the available balance in the fund is less than nine million dollars. The collected fees are placed in the PFAS Cash Fund established by the legislative bill. The funding is managed by the Water Quality Control Division and can be used for the PFAS grant program, PFAS takeback program, and PFAS technical assistance to impacted communities.

The PFAS Grant Program provides funding opportunities to eligible entities through three (3) primary project categories: 

1. Sampling - standard sampling and Independent Environmental Studies;
2. Emergency Assistance - to communities and water systems affected by PFAS; and 
3. Infrastructure -water system infrastructure for the treatment of PFAS and prevention strategies for upstream sources of PFAS.

The PFAS grant program has awarded over 19 million dollars in grant funds to help communities across Colorado identify and mitigate PFAS in water. Some current and past projects include:

• Determining the impacts of firefighting foam, ski wax, and septic systems on source water. 
• Piloting PFAS treatment for drinking water systems and landfill leachate.
• Installation of filtered drinking water stations in schools.
• Several fish tissue sampling efforts.
• Over $3.5 million to identify and assess PFAS in drinking water, source water, and groundwater. 
• ~$12 million used to implement PFAS treatment for clean drinking water.

A full list of awarded projects can be found on the PFAS Grant Summaries webpage.  In addition, our annual legislative reports on the program progress can be found on the PFAS Laws webpage.

Any questions may be directed towards the cdphe_wqcd_pfas_grant@state.co.us email. Please use the subject line “Grant Program Questions.”

➽ Sierra Mitchell, PFAS Program Coordinator

EPA PFAS Rule Update: What Colorado Water Systems Need to Know

The division is closely monitoring recent developments from the EPA regarding its 2024 drinking water PFAS Rule. While the EPA has signaled potential changes to the regulation, the official rulemaking timeline remains unchanged, with Colorado’s adoption scheduled for August 11, 2025. The division is committed to maintaining clarity for water systems and intends to highlight this federal uncertainty in its Statement of Basis and Purpose that is part of the rulemaking. The division is committed to communicating with water systems when federal action occurs and proposing revisions to Colorado’s PFAS rule to align with federal requirements before the Water Quality Control Commission.

Resources: 

• CDPHE - Regulating per- and polyfluoroalkyl substances (PFAS) in drinking water
• CDPHE - PFAS mapping (includes PFAS in treated drinking water map and data) 
• CDPHE - PFAS Grant program

EPA’s Announced Changes

In May 2025, the EPA announced that it may significantly revise the 2024 PFAS Rule. Proposed changes include:

• Removing and reconsidering regulations for four PFAS compounds: PFNA, PFHxS, HFPO-DA (GenX), and PFBS.
• Retaining Maximum Contaminant Levels (MCLs) and monitoring requirements for PFOA and PFOS only.
• Eliminating the Hazard Index concept and its associated MCL for PFAS mixtures.
• Extending the compliance deadline for PFOA and PFOS MCLs from 2029 to 2031.

These changes are planned to occur via a revised PFAS Rule proposal in Fall 2025, and anticipated finalization in Spring 2026.

It’s important to note that, so far, EPA’s announcement has not indicated changes to the requirements for initial monitoring of six PFAS compounds by the April 2027 compliance deadline.

Colorado’s Approach

Colorado is moving forward with adopting the PFAS rule this summer to retain full Safe Drinking Water Act primacy. This ensures that the division, not EPA, will continue to oversee PFAS compliance, monitoring, and enforcement across Colorado systems.

To account for the evolving federal landscape, the division has included a “federal flexibility provision” in its rule language. This provision allows for the automatic extension or stay of any deadlines or requirements altered by the final federal PFAS Rule, minimizing disruption for water systems.

Why Primacy Matters

Colorado’s decision to adopt the rule in 2025 avoids a primacy extension agreement with EPA. Under such an agreement, EPA would have authority over PFAS compliance while the state catches up. This would fragment regulatory oversight, complicate compliance for Colorado’s water systems, and limit our decision-making authority during this period. We believe that the division can provide the best decisions for water systems and their customers in Colorado.

The division’s experience with the Lead and Copper Rule Revisions (LCRR) demonstrated the benefit of timely rule adoption. Being one of the few states to implement LCRR on schedule allowed the division to retain control and better support systems through technical and operational challenges. The same advantages apply here.

Operational Implications for Water Systems

Drinking water data across Colorado shows that PFOA and PFOS are the primary PFAS compounds detected in public water supplies in Colorado. The removal of other compounds from the federal rule should not change which systems require PFAS treatment in Colorado. However, there may be impacts to treatment plant design and operation, which the division will work to consider during rule implementation.

In the meantime, systems are encouraged to stay engaged and continue monitoring for PFAS to meet initial monitoring requirements. The division will provide ongoing updates and technical assistance throughout this evolving process.

Stay Informed

The division is committed to supporting Colorado’s water systems during this transition. As the revised federal rule develops, Colorado will adapt, but always with the goal of maintaining clarity, consistency, and strong public health protections.

➽ Haley Orahood, Regulatory Development and Implementation Specialist

PFAS Rule and CCR Revisions: Update on Stakeholder Engagement on Rulemaking

In Spring 2024, EPA finalized the Per- and Polyfluoroalkyl Substances (PFAS) Rule and Consumer Confidence Report (CCR) Rule Revisions. The PFAs Rule will protect public health by requiring ongoing monitoring of “forever chemicals” beginning in 2027 and setting health-based limits starting in 2029. The CCR Rule Revisions modernize the content and delivery methods for all community systems and increases the frequency and accessibility of water quality reports for consumers served by larger systems beginning in 2027. 

In August 2024, the division launched a stakeholder engagement process in support of a rulemaking hearing before the Water Quality Control Commission to adopt these federal rules into the Colorado Primary Drinking Water Regulations (Regulation 11). Between August 2024 and January 2025, we held a total of seven stakeholder meetings and two workgroup meetings in support of the stakeholder process. We appreciate the significant contributions from water providers, environmental organizations, and members of the public. This collaboration is essential for developing effective and sustainable regulations that address the specific needs of our state.

Through the stakeholder process, we have:

• Developed Draft Regulatory Language: The feedback received from stakeholders has directly informed the development of draft language for the upcoming PFAS Rule and CCR Rule Revisions. 
• Created PFAS Rule Resources: To aid water providers in navigating the complex requirements, we have developed a PFAS Rule page with guidance and a frequently asked questions document, an initial monitoring compliance check worksheet to help understand the timing requirements for monitoring, and are in the process of developing tools to allow submission of UCMR 5 PFAS data for use in meeting initial monitoring requirements.
• Updated CCR Content: While most content changes under the CCR Rule Revisions are not required until 2027, there are a few changes to CCRs distributed in 2025 required under the Lead and Copper Rule Revisions. The division has updated CCR draft templates for 2025 to capture the language and content required to be included in CCRs.

Looking ahead, the next major milestone is the rulemaking process before the commission. This is a crucial stage where the commission will review the draft regulations, consider public input, and ultimately make a decision on whether to adopt these rules into Regulation 11.

Important Note: There has been some recent developments at the federal level. EPA has been granted abeyances by the DC Circuit Court concerning lawsuits regarding the federal PFAS Rule. These abeyances were granted to allow the new administration time to review the rule and the plaintiff’s petition to the Court. On May 14, 2025, EPA announced that it was considering delaying compliance with the PFAS standards but no specific mention was made about the testing requirements. We are actively monitoring this situation and will provide updates as they become available. None of this impacts the CCR rule. 

We recognize that navigating these regulations can be complex. Therefore, we are committed to keeping you informed throughout the process. We will provide updates on the rulemaking process and opportunities for public comment.

How to Stay Informed:

• Visit the Division's Engagement Website and sign up for notifications
• Attend Commission Meetings: Commission meetings are open to the public, and your participation is encouraged. For more information about upcoming meetings and hearings please visit the commission's website.

We believe that everyone plays a vital role in shaping water policy. By staying engaged, we can collectively work towards ensuring clean and safe drinking water for all Coloradans.

➽ Bryan Pilson Technical, Regulatory Implementation, and Coordination Unit Manager

CDPHE, EPA, & Wigwam Partnership for PFAS Treatment

Resources: 

For more information please visit 

• CDPHE PFAS Proarjects Website
• WQCD Grant Website

The Colorado Department of Public Health and Environment (CDPHE) is excited to highlight Wigwam Mutual Water Company’s PFAS pilot project as an excellent example of the Division’s culture of health initiatives. Wigwam is a small public water system, located in El Paso, County just south of Colorado Springs, that serves approximately 1,300 people. Their source water is drawn from the Fountain Creek alluvial aquifer and through pro-active testing the public water system detected elevated levels of certain PFAS in its drinking water. The test results came back above the established EPA Maximum Contaminant Level (MCL) of 4.0 parts per trillion (ppt) for Perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS). To address this emerging contaminant issue, CDPHE provided the community with point-of-use treatment to reduce PFAS levels to below the MCL while working towards the implementation of a more permanent treatment solution. This effort was promoted to ensure the community was provided with safe drinking water during the next planning and design phases of the project. 

Last year, CDPHE awarded Wigwam a $300,000 grant to pilot PFAS treatment technologies through the Emerging Contaminants in Small for Disadvantaged Communities (EC/SDC) grant program. This project has been a collaborative approach with direct assistance from the CDPHE, PFAS team and Engineering staff, the Environmental Protection Agency (EPA), and the EPA’s Office of Research and Development (ORD). Wigwam is planning to conduct pilot testing with Granulated Activated Carbon (GAC), Anion Exchange (AIX), and a new emerging technology, namely Electrocoagulation (EC). This innovative pilot project will compare the different treatment technologies and assist Wigwam in determining if the new EC technology is feasible and able to effectively treat PFAS in its drinking water. This collaborative approach will help ensure that this community has the best information to help them find a viable treatment solution to address this water quality challenge. After the study, EPA and CDPHE will utilize the treatment piloting results to provide an assessment of the treatment options for communities in order to effectively remove PFAS and other contaminants with reasonable and sustainable costs. 

CDPHE is excited to promote the partnership between EPA ORD and Wigwam to assist in this effort.

➽ Sierra Mitchell, PFAS Program Coordinator

Aqua Answers: PFAS and Biosolids

Dear Aqua Answers,

Please help! I have multiple questions about PFAS and biosolids. 

Thanks,

Newt R. Sludge

__________________________________________________________________________

Dear Newt,

I have listed your questions and the answers below:

Question 1:

Can you remind me, what are biosolids? 

Biosolids are a product of domestic wastewater treatment processes. They are rich in nutrients and organic matter; farmers can use them as fertilizer to improve soil quality. The Colorado Department of Public Health’s Water Quality Control Division and the U.S. Environmental Protection Agency require biosolids to meet regulatory requirements for pathogens, pollutants, and land application to protect human health and the environment. Biosolids produced in Colorado are either land applied to agricultural fields as a soil amendment/fertilizer (70+%), composted (20+%), or disposed of in landfills.

Question 2:

How do PFAS get into biosolids?

Industrial, commercial, and residential use and disposal of PFAS products can allow these chemicals to enter wastewater treatment facilities. As a result, researchers have found PFAS in treated wastewater and biosolids. PFAS can move in the environment and potentially impact the soil, water, and crops.

Question 3:

What is the department’s approach to reducing PFAS levels in biosolids? 

The department has taken a proactive approach that aligns with EPA’s newly released Draft Sewage Sludge Risk Assessment recommendations and focuses on measuring and understanding levels of PFAS in biosolids and identifying and reducing significant sources of PFAS migrating to wastewater treatment facilities. The department began implementing its Biosolids-PFAS Interim Strategy on January 1, 2023. It establishes monitoring requirements for biosolids preparers and a threshold level for requiring biosolids preparers to develop and implement a source control program to evaluate potential industrial or commercial sources of PFAS. More information about our interim strategy and biosolids test results the department has received are available on our PFAS and biosolids web page.

Question 4:

What can people living in our beautiful state do to reduce the amount of PFAS entering the environment? 

Over the past several years, Colorado has committed to identifying where PFAS are entering the environment, stopping new releases, and protecting Coloradans. In many ways, Colorado has led the way in its efforts to track and reduce exposure to PFAS. The department is now focusing on carrying out actions in the 2024 PFAS Action Plan to continue our work as a leader among states addressing widespread PFAS pollution. To learn more, please visit the 2024 PFAS Action Plan webpage.

To protect the environment and reduce the amount of PFAS entering our wastewater treatment plants, we need to phase out the production and use of products containing these chemicals and find safer alternatives. Recent legislation in Colorado has banned the sale of certain products containing PFAS. We encourage people to get the facts and take steps to limit their exposure from other sources and avoid PFAS when purchasing consumer goods and new household products. This will protect your health and further prevent the chemicals from entering our environment. We have resources at our PFAS public health website.  

Sincerely,

Aqua Answers

Design Criteria Update 2024

The Design Criteria for Potable Water Systems (Safe Drinking Water Program Policy 5) are a key policy document for the department to make decisions on approval of new designs for water sources, treatment, and storage facilities. The document also serves as a guideline for repairing or upgrading waterworks that are cited as significant deficiencies during the department’s sanitary surveys. While systems are not required to modify their waterworks to meet the design criteria unless their current waterworks are deficient, they are required to consider the criteria as acceptable fixes whenever their current waterworks are found to be deficient.

The Design Criteria were last updated in 2022. While the Department generally performs updates every 4-5 years, the department decided that a limited update was needed in 2024 because the Environmental Protection Agency (EPA) set maximum contaminant levels (MCLs) for five per and polyfluoroalkyl substances (PFAS) in April 2024. 

This update incorporated PFAS treatment criteria into Chapter 4 - Treatment, and added PFAS to the source water testing requirements in Chapter 1.2.3 Water Quality Data. The Department also used the update project as an opportunity to address internal and external feedback on Chapter 7 - Storage Tanks, and Appendix A, and align these sections more accurately with our existing business processes. Editorial changes were made throughout these sections to correct errors and inconsistencies and clarify language.

Like in previous updates, the department convened groups of stakeholders to work on the criteria. There were two external workgroups and one internal workgroup: Storage Tanks, PFAS Treatment, and Appendix A (design review submittal requirements). Generally, the overall structure of this document remained the same between 2013, 2017, 2022, and 2024 including section headings and names. The following describes the updates to each section that came out of the workgroups:

• PFAS Treatment: The PFAS treatment workgroup incorporated treatment requirements for PFAS removal to align with EPA’s PFAS MCL. This update primarily focused on 4.10 Adsorptive Media. The updates to this section include minimum empty bed contact times and maximum flow rates for granular activated carbon, non regenerating ion exchange, and engineered resin media. Additional design submittal requirements were added for media selection justification, design capacity, operations and control strategy. Language was also added outlining when piloting is and is not required for adsorptive media treatment systems. The workgroup took into consideration the impacts that the updated requirements would have on small public water systems. 
• Storage Tanks: The storage tank workgroup focused on updating Chapter 7. The workgroup added language in 7.0.10 Roof and Sidewall that no longer allows corrugated roofs on storage tanks and clarified the requirements for storage tank interior construction materials due to difficulty protecting these types of roofs from contamination. The workgroup also further clarified requirements for vents, overflows, drains, and access openings after gathering internal and external feedback since the last update. 
• Appendix A: The internal Department workgroup updated Appendix A which covers the design review submittal requirements. This workgroup aligned Appendix A with the current Department business practices. Appendix A, Table A.1 was updated and now outlines if a waterworks project needs: Department design review, monitoring plan updates, professional engineer for community water systems, and the corrosion category. The workgroup's effort resulted in changes to the Design Criteria and not just Appendix A. 
• The Introduction and Chapter 1 were updated to reflect the changes to Appendix A including the removal of the limited scope process. 
• Chapter 4, Section 4.4.2 was updated related to 4-log virus inactivation capacity for triggered groundwater systems. Section 4.4.2 was updated to align with the Regulation 11 requirement for groundwater systems to maintain 0.2 mg/L at the entry point instead of requiring the capacity for 4-log virus inactivation. The Department still strongly recommends 4-log virus inactivation for triggered groundwater systems but the Department does not have staff resources to devote to this requirement given the limited amount of Fecal Indicator-Positive monitoring events in Colorado. The Department also has a strong and long-standing approach to evaluating water sources for being under the direct influence of surface water, so we do not view this change as jeopardizing public health protection.

➽Chelsea Cotton, Lead Drinking Water Engineer

New Grant Provides Money for Emerging Contaminants!

The division has been awarded $86 million from the EPA to implement the EPA Emerging Contaminants for Small or Disadvantaged Communities Grant Program (EC-SDC). The purpose of the program is to assist public water systems in small or disadvantaged communities with planning and design grants, and infrastructure funding to reduce public health risks from emerging contaminants.

The division is implementing the grant program in a multi-round Request For Application (RFA) process for public water systems under two tiers: Tier 1 is a planning and design grant up to $300,000. Tier 2 is a construction grant in award amounts up to $10M per year for up to three years. The program places priority on PFAS treatment projects followed by manganese and other drinking water emerging contaminants. More information regarding program details can be found on the WQCD Water Quality Grants webpage under the EC-SDC blue banner.

In order for projects to be eligible for this funding they must be governmental or private non-profit public water systems, be considered disadvantaged, and have an identified emerging contaminant issue through direct sampling. The program is focused on addressing issues related to PFAS, but manganese is also considered an emerging contaminant and can be funded through this program. If your system has not completed any PFAS sampling yet, you can qualify for a one time sampling of your finished drinking water for PFAS. Use this form to request PFAS sampling for your public water systems.

The program has already funded a number of projects including a new water plant to treat PFAS, a pilot study to evaluate new technology to treat emerging contaminants, and a planning grant to conduct studies to determine system improvement options for treating PFAS and manganese. 

The division plans to release an RFA near the beginning of 2025 and systems are encouraged to apply for this grant opportunity. The RFA will be announced on the WQCD Water Quality Grants webpage under the EC-SDC blue banner. There will also be an announcement sent out to all subscribers of our listserv under the topics of “General - Grants and Loans” and “General - PFAS (Toxic Firefighting Foam Chemicals)”. Please go to the Stay Informed - Water Quality site to subscribe to these and other lists. If you have any questions or you would like to discuss a potential project please reach out to cdphe_wqcd_ec_sdc_grants@state.co.us.

➽ Mark Henderson, Section Manager, WQCD Community Development & Partnership Section

PFAS: Upcoming Stakeholder Information and Answers to Common Questions

Stakeholder meeting for regulating per- and polyfluoroalkyl substances (PFAS) in drinking water

The Water Quality Control Division will host our kickoff meeting on Thursday, Aug. 22, 2024, from 1 to 2:30 p.m to discuss the statewide adoption of the EPA’s PFAS National Primary Drinking Water Regulation under the Water Quality Control Commission’s Regulation No. 11. 

• Register for the PFAS kickoff meeting 

We invite all interested individuals to participate in the process but strongly encourage community and non-transient, non-community public water systems to attend. 

• Sign up through the PFAS drinking water rule engagement form if you would like to continue to receive email correspondence regarding this process.

PFAS Questions

What just happened with the PFAS rule?

On April 10, 2024 the Environmental Protection Agency (EPA) set maximum contaminant levels (MCLs) for five individual PFAS: PFOA, PFOS, PFNA, PFHxS, and HFPO-DA (known as GenX). The EPA is also setting a Hazard Index level for two or more of four PFAS as a mixture: PFNA, PFHxS, HFPO-DA, and PFBS.

Chemical	Maximum Contaminant Level Goal (MCLG)	Maximum Contaminant Level (MCL)
PFOA	0	4.0 ppt
PFOS	0	4.0 ppt
PFHxS	10 ppt	10 ppt
HFPO-DA (GenX Chemicals)	10 ppt	10 ppt
PFNA	10 ppt	10 ppt
Mixture of two or more: PFHxS, PFNA, HFPO-DA, and PFBS	Hazard Index of 1 (unitless)	Hazard Index of 1 (unitless)

Table 1. New federal PFAS Regulatory Levels

Definitions

Maximum Contaminant Level Goal (MCLG): The level of a contaminant in drinking water below which there is no known or expected risk to health and allows for an adequate margin of safety. MCLGs are non-enforceable public health goals.  

Maximum Contaminant Level (MCL): The highest level of a contaminant that is allowed in drinking water. MCLs are set as close to MCLGs as feasible using the best available treatment technology and taking cost into consideration. MCLs are enforceable standards.   

Parts per trillion (ppt):  A ppt is a measurement of the quantity of a substance in the air, water or soil. A concentration of one part per trillion means that there is one part of that substance for every one trillion parts of either air, water or soil in which it is contained. One part per trillion is equivalent to one nanogram per kilogram ng/L.

Hazard Index (HI): The Hazard Index is a long-established approach that EPA regularly uses to understand health risk from chemical mixture. The HI is made up of a sum of fractions. Each fraction compares the level of each PFAS measured in the water to the highest level determined not to have risk of health.

What is a Hazard Index?

Research shows that mixtures of PFAS can have additive health effects. This means that low levels of multiple PFAS that individually would not likely result in adverse health effects may pose health concerns when combined in a mixture. EPA’s Hazard Index MCL is set at 1 and applies to any mixture containing two or more of PFNA, PFHxS, PFBS, and GenX. The Hazard Index is made up of a sum of fractions. Each fraction compares the level of each PFAS measured in the water to the highest level below which there is no risk of health effects.

Is this going to impact my water system?

Community Water Systems and Non-Transient Non-Community Water Systems must comply with the PFAS drinking water MCLs. Consecutive community systems and NTNC systems must comply with the MCLs as well but the requirements are less extensive.

When will I see this on my Monitoring Schedule? When do I need to start sampling? Am I going to need to install treatment?

By the end of 2026: 

• Systems must conduct initial monitoring or obtain approval to use previously collected monitoring data
• States must adopt PFAS rule into state regs

Starting in 2027: 

• Systems must start their ongoing compliance monitoring
• There are opportunities for reduced monitoring depending on the system’s initial monitoring results
• Systems must include results of their monitoring for the regulated PFAS in their Consumer Confidence Reports
• Systems must start issuing public notification for any monitoring and testing procedure violations

By the end of 2028:

• Systems that detect PFAS above the new standards must implement solutions that reduce PFAS in their drinking water to below the MCLs to remain in compliance with the rule

Starting in 2029: 

• Systems must comply with all regulated PFAS MCLs
• Systems must provide public notification for violations of the PFAS MCLs

What treatment methods will remove PFAS?

• Granular activated carbon (GAC), ion exchange and reverse osmosis are the most common methods of removing PFAS from drinking water. 
• Most conventional drinking water treatment methods will not remove PFAS.
• Powdered activated carbon (PAC) may remove some PFAS but testing is required to confirm.
• PFAS is not removed by boiling.

How do I deal with PFAS treatment residuals?

The EPA released an interim disposal guidance for PFAS media, backwash water, and RO concentrate. Their current recommended methods are:

• Underground injection
• Landfill
• Thermal treatment/incineration - this is the best option but isn’t widely available yet. Note that exhausted GAC media can be thermally regenerated for non potable use. 
• Interim storage for high PFAS content materials.

Are there labs to do this testing? Is it expensive?

• Testing costs vary from lab to lab and typically range from about $300 to $600 per sample. Systems must use an approved test method (EPA 533 or EPA 537.1) Be aware that there are lower cost PFAS tests available and while these may be good for applications like testing a private well, they may not be acceptable for compliance purposes. 
• Systems can sign up for CDPHE’s grant program for initial PFAS monitoring or reach out to cdphe_wqcd_pfas_grant@state.co.us.
• All labs on the EPA’s list of labs certified for PFAS testing are acceptable for compliance purposes.

Where can I find more information?

• CDPHE's Water Quality PFAS website
• EPA’s Water Quality PFAS Website
• CDPHE's PFAS testing results in public water systems in Colorado

➽ Chelsea Cotton, Lead Drinking Water Engineer

PFAS Wastewater/Biosolids Sampling - SB20-218

Image courtesy of Michigan Department of Environment, Great Lakes, and Energy

The Department of Public Health and Environment (CDPHE) is pleased to announce a new program offering wastewater and biosolids facilities free lab analysis of wastewater and biosolids samples for PFAS. The program will be available during fiscal year 2025 (July 1, 2024 thru June 30, 2025) and funding dependent moving forward. To request a sample kit, please complete the Wastewater/Biosolids PFAS Sampling Request form located on the PFAS grant program webpage. 

The division has been implementing a proactive approach to control PFAS contributions to the environment that includes measuring and trying to understand levels of PFAS in biosolids and wastewater. The concept is to identify and reduce significant sources of non-domestic PFAS entering wastewater treatment facilities.

For more information visit the CDPHE's PFAS website and PFAS and Biosolids website. 

➽ Sierra Mitchell, PFAS Program Coordinator

PFAS Treatment and Best Available Technologies

As we discussed in the May 8th Aqua Talk article May 8th Aqua Talk article, EPA has released its final PFAS MCLs. The May 8th article summarizes the new rule and gives an overview of what water systems will need to do to come into compliance with the new rule. Today we will talk about typical PFAS removal technologies and  the upcoming update to the Design Criteria for Potable Water Systems, also known as Safe Drinking Water Program Implementation Policy #5, to incorporate PFAS treatment technologies. 

Policy #5 is used as a basis for reviewing design applications for drinking water treatment works in Colorado. The division routinely updates the document to maintain industry standards with input from stakeholders. The division is initiating a stakeholder process in 2024 and asking for feedback on portions of the drinking water design criteria to be updated. If you are interested in participating in this process please visit the Drinking Water Design Criteria stakeholder engagement website Drinking Water Design Criteria stakeholder engagement website. 

The division is aware that there are drinking water systems in Colorado that are looking to implement PFAS removal prior to the completion of the design criteria update. For those systems there are additional resources available. The EPA has released a guidance document for water systems titled Treatment Options for Removing PFAS in Drinking Water. The EPA has identified best available technologies (BAT) for PFAS removal using six criteria: 

• removal efficiency, 
• historical full scale operation, 
• geographic applicability, 
• compatibility with other treatment processes, 
• ability to bring the entire water system into compliance, 
• and a reasonable cost to large as well as medium sized systems

The technologies identified are granular activated carbon (GAC), ion exchange (IX), and reverse osmosis (RO). 

Granular Activated Carbon (GAC) is a process where adsorptive media is contained in pressure vessels or atmospheric filter beds. The PFAS contaminated water passes through the vessel or bed and the dissolved contaminants are pulled from the water and onto the surface of the media. In addition to removing PFAS, GAC can remove other contaminants including taste and odor compounds, volatile organic compounds, disinfection byproduct precursors, and others. For this reason, GAC is great for water systems looking to address multiple concerns at once. GAC will generally not have a significant impact on the corrosivity of the water. After a period of time, the GAC media will not be able to adsorb any more contaminants and will need to be replaced by fresh media and properly disposed of. The EPA has published an Interim Guidance on the Destruction and Disposal of PFAS and Materials Containing PFAS. Disposal methods include landfills and thermal treatment for regeneration or destruction. 

Ion exchange (IX) is similar to GAC where contaminated water is passed through a media, but rather than adsorbing contaminants, the PFAS in the feed water are exchanged for an ion, such as chloride, on resin beads contained in a pressure vessel. The IX process continues until the resin is out of chloride exchange sites. Unlike other IX treatment applications like water softening, the spent resin can not be regenerated by backwashing. The resin will need to be periodically disposed of and replaced with fresh media. This treatment process generally targets PFAS only and will not remove additional contaminants. The IX process tends to require a smaller footprint than GAC. Due to the addition of chloride ions into the IX effluent, this treatment process may impact the corrosivity of the finished water. Spent IX resin must either be landfilled or incinerated. 

There are other PFAS selective media available on the market today. For any of these newer media, GAC or IX resins, pilot testing is recommended to determine what method works best for a specific water quality. Piloting allows the water system to look at factors like comparative costs, treatment efficacy, and secondary impacts to finished water quality whether beneficial or not. 

The third technology that EPA has identified is reverse osmosis (RO). RO is a membrane separation process that physically removes contaminants from drinking water. This process results in two streams of water: the clean effluent and a reject stream that contains concentrated PFAS and other contaminants. The disposal of this continuous waste stream can be a substantial challenge in Colorado. The most common disposal method for land-locked states is deep well injection or evaporation ponds. There are other disposal methods in the research phase. 

There are many factors that should be considered as a water system addresses compliance with the PFAS MCLs. For some systems there may be a non-treatment option that is a better fit. Non-treatment options include adjusting source water blending ratios to prioritize sources with lower PFAS levels, an interconnect into a system with existing PFAS treatment, or consolidation into an existing system. If you would like to talk to us more about what available treatment options and grant funding opportunities, please email us at cdphe_pfas@state.co.us.

Thank you,

➽ Chelsea Cotton, P.E. Lead Drinking Water Engineer

Final PFAS Rule Considerations

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