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On March 24, 2023, the Environmental Protection Agency recently announced Maximum Contaminant Levels (MCLs) for six PFAS substances. Please see updated information under the "Are PFAS regulated?" tab below.

Some products that contain PFAS

You may have been hearing about PFAS in the news and have questions. PFAS, an abbreviation for perfluoroalkyl and polyfluoroalkyl substances, is a common term for a group of human-made chemicals found in everyday products. Thousands of these substances are used to manufacture products sold globally and have been around since the 1940s.

These products were originally created to make our lives easier, as they are resistant to water, grease and stains. They are also used in firefighting foams, primarily at airfields. Researchers, however, have found that there may be health effects associated with exposure to some PFAS. 

Industrial, firefighting foam and consumer products are the most common sources of PFAS  –  use of these products has introduced PFAS into our water supplies. Controlling PFAS at the source is the best way to keep it out of the environment.


Why are we hearing about PFAS now if they've been around for decades?

PFAS compounds are difficult to detect. They exist in most products at extremely miniscule levels. It’s only recently that laboratory testing technology could even see them at the levels being discussed.

Technological advances now allow us to detect concentrations in the parts-per-trillion (ppt) range. The health advisory limits, however, are below what can be currently detected. The scientific understanding and regulatory response to these compounds is uncertain but rapidly evolving. This includes potential public health implications.

Aurora Water is closely monitoring the new EPA drinking water guidelines for PFAS chemicals and will be working with the state to protect public health. Aurora Water will always use the latest and best available technology to monitor and safeguard your drinking water.

Are PFAS regulated?

National drinking water quality standards are set by the EPA and administered in our state by the Colorado Department of Public Health and Environment (CDPHE). Under the Safe Drinking Water Act, the EPA issues national health-based standards for drinking water to protect against both naturally occurring and man-made substances that may be found in drinking water.

To date, PFAS compounds (a group of thousands of per and polyfluoroalkyl substances) are not regulated.

On March 24, 2023, EPA announced MCLs for six PFAS. If finalized, the proposal would regulate PFOA and PFOS as individual substances, and PFHxS, PFNA, PFBS and HFPO-DA (commonly referred to as GenX) as a PFAS mixture. The EPA is also proposing health-based, non-enforceable Maximum Contaminant Level Goals (MCLGs) for these six PFAS.

The MCL is the highest level of a substance that is allowed in drinking water. MCLs are enforceable standards set by the EPA.

The proposed regulations include the following:
• PFOA and PFOS: EPA is proposing to regulate PFOA and PFOS at a level they determined can be reliable measured at 4 parts per trillion (ppt).
• PFNA, PFHxS, PFBS and GenX: EPA is also proposing a regulation to limit any mixture containing one or more of these chemicals.
• For these PFAS, water systems would use an established approach called a hazard index calculation, defined in the proposed rule, to determine if the combined levels of these PFAS pose a potential risk. This program was designed to help water providers across Colorado. The MCL for the PFAS mixture would be a hazard index of 1.

EPA requested public comments on the proposed MCLs in May. All public comments received by the EPA will be evaluated before a final standard is adopted. Public water systems will have a certain number of years to comply with the new standards once it is finalized.  

What is a health advisory?

A health advisory provides information on substances that can cause negative human health effects. Health advisories are non-enforceable and non-regulatory.

The health advisory levels were calculated to offer a margin of protection for all people, including sensitive populations and ages, against adverse health effects and take into account other potential sources of exposure beyond drinking water (for example, food, air, consumer products, etc.). Because these substances have been used in an array of consumer products, most people have been exposed to them and have them in their system. According to the Centers for Disease Control (CDC), the average concentration (geometric mean) measured in the general U.S. population during 2017-2018 was 1.4 parts per billion (ppb) of PFOA and 4.3 ppb of PFOS.

Potential health effects

Research has shown there may be health effects associated with exposure to some PFAS. Because there are many types of PFAS chemicals, which often occur in complex mixtures and in various everyday products, researchers face challenges in studying them. More research is needed to fully understand all sources of exposure, and if and how they may cause health problems. The National Institute of Environmental Health Sciences (NIEHS) provides updated information on health effects as well as a searchable database of published scientific papers about PFAS, which can be found here.

Why aren't PFAS listed in the 2022 Water Quality Report?

Our labs test more than 85,000 samples system-wide to ensure that the water we deliver to your house everyday meets and exceeds all state or federal regulatory standards. Every year, we provide a Water Quality Report that shows the results of our continuous laboratory testing for regulated substances. To date, PFAS compounds are not regulated.

Prior to June 15, 2022, the EPA had a health advisory limit for two PFAS compounds (PFOA and PFOS) at 70 parts per trillion. Aurora’s drinking water had tested well below that limit for PFOA and PFOS.

Aurora Water's treatment process 

Public health and the quality of your drinking water is Aurora Water’s top priority. Aurora’s water continues to meet or exceed all state and federal drinking water standards.

Aurora Water strives to provide clean, safe, great-tasting drinking water to its customers. Aurora’s water comes primarily from high-quality surface water sources originating from high in the mountains. We use direct and conventional filtration to treat our mountain water.

The city also uses river water from the South Platte River through the Prairie Waters System. This system recaptures water using a multibarrier process that includes granular activated carbon, which is an approved technique to reduce PFAS levels.

What is Aurora Water doing about PFAS?

Aurora Water is committed to protecting our residents and our resources. Staff have been engaged in numerous discussions at Federal, Regional and State levels (including regulators and legislators) stressing the importance of appropriately regulating, managing and remediating PFAS substances. The multibarrier approach used in our treatment system means we have flexibility in treating new substances.

These communications have included the importance of holding those parties who introduced the PFAS into the environment responsible for remediation and clean-up and the importance of prohibiting additional use of PFAS compounds in the manufacture of goods.

In 2022, Colorado Governor Jared Polis signed into law the most comprehensive state bill restricting the sale of PFAS in consumer products, as well as fluids used in the extraction of oil and gas products, as early as 2024. Eliminating PFAS at the source is the best way to keep it out of the environment. Staff will continue to engage in these discussions.

Aurora Water also investigates potential solutions using a pilot treatment plant, which is housed in the Binney Water Purification Facility. This pilot plant is used to test a variety of water treatment processes’ efficiency, capability and effectiveness. The pilot plant system, which operates independently from the rest of our water treatment processes, allows operators to further research PFAS reduction processes.

We also support a growing body of peer-reviewed scientific research on PFAS. As a leader in the water industry, Aurora Water is engaged in stakeholder and other local, state and national opportunities to develop solutions. Aurora Water will continue to closely monitor the EPA’s guidelines on PFAS to inform our next steps.

If PFAS are in so many consumer goods, why haven't I heard about the PFAS levels in them?

Drinking water providers test their product more than just about any other industry. Water quality is highly regulated, primarily through CDPHE, which is the enforcement of the EPA’s Safe Drinking Water Act and Clean Water Act. Measuring PFAS in water is easier compared to measuring exposure from other sources of PFAS like clothing, food packaging or dental floss.

How can you help protect water quality?

We encourage residents to avoid PFAS when purchasing consumer goods and new household products. This will not only protect your health but also prevent the compounds from further entering our environment. For a list of PFAS-free consumer goods, visit PFAS Central.

I received information about a water filter, but a company gave me a quote that cost hundreds or thousands of dollars. Do I really need a water filter?

Aurora Water does not recommend installing home filtration devices. It’s more effective to treat water systemwide where it can be managed by trained, licensed water treatment professionals and supported through our state-of-the-art laboratory. If you do use a filter, for example with your refrigerator’s water or ice dispense, please make sure that you replace the filter regularly based on the manufacturer’s recommendation.

Surrounding communities have received reports of companies using predatory sales tactics to scare customers into paying more than they need to on water treatment options. Expensive water filtrations systems are absolutely not necessary for anyone with Aurora Water.

Voluntary sampling and results

  • In 2020, Aurora Water participated in CDPHE’s PFAS voluntary sampling program.

  • This program was designed to help water providers across Colorado and the communities they serve determine if PFAS are present in their drinking water.

  • Prior to June 15, 2022, only PFOA and PFOS had advisory limits set at 70 ppt. At the time of sampling, we were below these limits.

  • As of June 15, 2022, the EPA released much lower health advisories for two PFAS compounds PFOA and PFOS and issued health advisories for two new compounds – GenX and PFBS.

    These HALS were set at: 
         PFOA 0.004 ppt (interim)
         PFOS 0.02 ppt (interim)
         GenX 10 ppt (final)
         PFBS 2,000 ppt (final)

  • In the summer of 2022, Aurora Water retested the water and the latest sampling data is shown below.

  • On March 24, 2023, EPA proposed MCLs for six PFAS. See additional information under the "Are PFAS regulated?" tab.
PFAS EPA Proposed MCL 2022 Source Water Results 2022 Finished Water Results
PFOA 4 <2-15 ≈0.47-0.57
PFOS 4 <2-15 ≈0.030-0.35

Gen X


as a combined health index



*All numbers are in parts per trillion (ppt)
≈ Indicates approximate values.

Aurora Water will continue testing for PFAS as part of our monitoring protocols. While we can effectively treat PFAS, we regularly examine our treatment system and adjust these processes as part of our mission to provide safe, dependable and sustainable water now and in the future.

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