PFAS In Drinking Water

What are PFAS and where do they come from?

"PFAS" is an abbreviation that stands for per- and polyfluoroalkyl substances, which are a family of approximately 5,000 human-made chemicals dating back to the 1940s that include perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). While common uses have included nonstick cookware, food packaging, building and exterior use products, water repellent clothing, some fire-fighting foams, and stain proof carpeting, PFAS have been used in a wide range of manufacturing and industrial activities due to these chemicals' durable and oil- and water-resistant properties. This has resulted in PFAS being released into the air, water and soil. While many PFAS have been phased out of use in the US, they are considered “forever chemicals” because they persist in the environment.

Scientists are studying the impacts of these compounds on the environment and human health. Though typically found in minuscule amounts, PFAS are found nearly everywhere.

Source: Illinois Environmental Protection Agency: Per- and Polyfluoroalkyl Substances (PFAS)

PFAS source infographic

Source: American Water Works Association

Are PFAS levels regulated?

The US Environmental Protection Agency (US EPA) regulates drinking water by setting limits, known as Maximum Contaminant Levels (MCLs). MCLs are numeric standards that have been established for more than 90 chemicals, using the best available analytical and water treatment technologies while taking into consideration costs for treatment. In 2016, US EPA set "Lifetime Health Advisory Levels" for PFOA and PFOS at 70 parts per trillion (ppt) combined. A Lifetime Health Advisory Level is only guidance for evaluating the prevalence and occurrence of unregulated drinking water contaminants. It is not an enforceable drinking water standard. US EPA has not set MCLs for any PFAS chemicals.

Similarly, the state of Illinois has not adopted MCLs for any PFAS chemicals. The Illinois EPA is considering whether to regulate PFAS in Illinois drinking water and is conducting a statewide investigation into the prevalence and occurrence of PFAS in finished drinking water at all 1,749 community water supplies in Illinois.

The Illinois EPA indicates that they will use data gathered by this investigation to inform possible development of future state drinking water standards. In the interim, the Illinois EPA has developed "Health-Based Guidance Levels" for certain PFAS chemicals, which are intended to be protective of all people consuming water over a lifetime of exposure. These Health-Based Guidance Levels are not enforceable drinking water standards. Rather, the Health-Based Guidance Levels are benchmarks against which sampling results may be compared to determine if additional investigation or response may be warranted.

Source: Illinois Environmental Protection Agency: Per- and Polyfluoroalkyl Substances (PFAS)

EPA Releases Drinking Water Health Advisories for PFAS

On June 15, 2022, the U.S. Environmental Protection Agency released drinking water health advisories (HAs) for four per- and polyfluoroalkyl substances (PFAS). Health advisories provide states and water utilities with a reference point as they evaluate potential contamination and appropriate responses to assure the safety of drinking water.

Perfluorooctanoic Acid (PFOA) and Perfluorooctane Sulfonate (PFOS) are two of the most widely used and studied chemicals in the PFAS group. The PFOA and PFOS health advisory levels are extremely low and do not reflect the draft recommendations of EPA’s own expert Science Advisory Board review. The health advisory levels are undetectable by modern laboratory methods. These four health advisories reflect potential risk assuming 70 years of exposure. (See EPA fact sheet.)

Interim Lifetime Advisories

  • Perfluorooctanesulfonic acid (PFOA) - 0.004 ppt
  • Perfluorooctanesulfonic acid (PFOS) - 0.020 ppt

Final Lifetime Health Advisories

  • Hexafluoropropylene oxide dimer acid (GenX) - 10 ppt
  • Perfluorobutanesulfonic acid (PFBS) - 2,000 ppt

The interim lifetime PFOA and PFOS HAs replace the previous 70 ppt advisory value released in 2016.

Are there health effects related to PFAS exposure?

Research on the potential health effects of PFAS is ongoing. PFAS continues to be present in a wide range of consumer goods, including food packaging and personal care products, as well as in the soil, air and water. Due to their durable characteristics, PFAS are bioaccumulative, which means that they can build up over time. While exposure does not necessarily mean that a person will get sick or experience an adverse health effect, current scientific studies have potentially linked PFAS exposure to increased cholesterol levels, increased risk for thyroid disease, low infant birth weights, reduced response to vaccines, liver and kidney toxicity, and pregnancy-induced hypertension.

Source: Illinois Environmental Protection Agency: Per- and Polyfluoroalkyl Substances (PFAS) Health Effects

Are there PFAS in the Village's drinking water?

The Village collects samples for these PFAS quarterly as a result of recommendations from the Illinois EPA. At this time, no enforceable federal or state drinking water standard, called a Maximum Contaminant Level or MCL, exists for PFAS chemicals. At the national level, EPA is in the process of establishing MCLs for PFAS within the scientifically rigorous framework of the Safe Drinking Water Act (SDWA).

The Village of Northbrook Water Plant's most recent results for the four PFAS:

PFAS Test Results 5.15.2023

Included below are the all the testing results that the Village has performed for PFAS. Raw denotes water received from Lake Michigan prior to treatment while Tap denotes the finished, treated water that leaves the Water Treatment Facility.

PFAS Test Results Analytical Results 5.15.2023

The concentrations detected in Village water are well below the US EPA published Lifetime Health Advisory Level of 70 parts per trillion (ppt). Notably, both the US EPA Lifetime Health Advisory Levels and Illinois EPA Health-Based Guidance Levels are measured in ppt, where many drinking water compounds are measured in parts per billion (ppb). As a frame of reference, one part per trillion is roughly the equivalent of one drop in 20 Olympic-sized swimming pools.

What is the Village of Northbrook doing?

On November 16, 2021 the U.S. Environmental Protection Agency (EPA) asked the agency’s Science Advisory Board to review draft scientific documents regarding the health effects of certain Per- and Polyfluoroalkyl Substances (PFAS). EPA is committed to science-based approaches to protect public health from exposure to PFOA and PFOS, including by quickly updating drinking water health advisories with new peer-reviewed approaches and expeditiously developing National Primary Drinking Water Regulations (NPDWRs) for these contaminants (proposed rule fall 2022, final rule fall 2023). NPDWRs are legally enforceable standards that apply to public water systems. Primary standards protect public health by limiting the levels of contaminants in drinking water.

The Village is following recommendations from the Illinois EPA and closely monitoring the latest health-based guidance. We will continue monitoring PFAS values through quarterly sampling at the direction of the Illinois EPA. The most recent test results will be added to the above chart on this web page, once available.

Which water treatment technologies are the water utility evaluating that are effective at removing PFAS in drinking water?

The Northbrook water production plant would begin assessing treatment technologies that can effectively remove PFAS from drinking water once the final rule has been proposed and adhere to the final rule making guidance. The treatment technologies include activated carbon treatment, ion exchange resins, and high pressure membranes, like nanofiltration or reverse osmosis. Below is a brief summary of each treatment option:

Granular Activated Carbon (GAC) – Chemicals like PFAS stick to the small pieces of carbon as the water passes through.

Powdered Activated Carbon (PAC) – The carbon is powdered and is added to the water. The chemicals then stick to the powdered carbon as the water passes through.

Ion Exchange Resins –Small beads (called resins) are made of hydrocarbons that work like magnets. The chemicals stick to the beads and are removed as the water passes through.

Nanofiltration and reverse osmosis –A process where water is pushed through a membrane with small pores. The membrane acts like a wall that can stop chemicals and particles from passing into drinking water.

There are things to consider with each of these technologies, including costs and operational feasibility, which would need to be weighed by the needs of the community as well as our wholesale customer base. These technologies can be used in drinking water treatment facilities, in water systems in hospitals, or individual buildings or even in homes.

Should I drink bottled water?

Not necessarily. If you choose to drink bottled water, check to make sure you are obtaining bottled water from a supplier who is testing for PFAS in their water supply, or that your bottled water is treated through a process to remove PFAS, such as reverse osmosis.

The International Bottled Water Association (IBWA) has established the following limits for their members providing bottled water to consumers:

5 parts per trillion for one PFAS
10 parts per trillion for more than one PFAS

A list of IBWA members can be found on their website. Please note that this group does not represent all bottled-water manufacturers. Also, look on the bottled water label for information about reverse osmosis or activated carbon filtration methods as they are the two technologies most commonly used for PFAS removal.

Are there home water treatment options?

Yes. Home point of use (POU) filters can help reduce/remove PFAS chemicals. A few brands that have had favorable results are:


Household removal of PFAS from drinking water requires the use of products such as granular activated carbon, reverse osmosis (RO), or anion exchange filters. These may be point-of-use treatments installed underneath the kitchen sink or countertop pitcher options that are refilled by the consumer as needed; both options require the filters to be changed at regular intervals. For private water well users who do not receive water from a community water supply, certified whole home treatments may be an option. When choosing a treatment, consider water usage, which faucets are used for water for drinking, cooking and making ice, and the type of PFAS identified through testing. Refrigerators with water and ice dispensers may need to be connected to the treatment source.

Treatment options should be tested by an independent third party to show effectiveness of reducing PFAS. NSF International has a list of filtration systems that have been certified to remove PFOA and PFOS. Products can be certified through NSF Protocol P473, NSF/ANSI Standard 53 (filters), or NSF/ANSI Standard 58 (reverse osmosis) to ensure the uniform testing of treatment filters to effectively reduce and remove PFOA and PFOS. Since other PFAS vary in their chemical makeup, they may not be removed as efficiently.

It is important to follow the manufacturer’s recommendations on how to properly maintain and change filters for the type of treatment you choose. Used filters should be disposed of in household trash.

The cost of treatment depends on the type of treatment chosen. Initial costs can range from $100 - $1,200 with annual media (filter) replacement costs around $200 each year.

Boiling water does not destroy PFAS. You can safely use your water for bathing and showering as PFAS is not easily absorbed into the skin.

Where can I find more information?

Illinois Environmental Protection Agency
Barb Lieberoff, Office of Community Relations

Illinois Department of Public Health
Brian Koch, Division of Environmental Health

If you have questions for the Northbrook Water Production Plant, please email Joe Rizzo, Utilities Superintendent, at or call 847-272-4711. The 2021 Annual Water Quality Report contains information about the Village's water quality.