What are PFAS?

Per- and polyfluoroalkyl substances (PFAS) are manmade compounds that can be found in a wide range of products such as:

  • Clothing
  • Furniture and carpeting
  • Repellants
  • Lubricants
  • Paint
  • Dental floss
  • Cosmetics
  • Food packaging
  • Non-stick cookware
  • Chrome plating
  • Firefighting foam
Image of items that may contain PFAS such as cookware, clothing, makeup and furniture.


PFAS have been around since the 1940s and are found throughout our environment. They do not degrade easily, are not easily destroyed and can persist in the environment for many years. Research indicates that high levels of certain PFAS may impact health. The Agency for Toxic Substances and Disease Registry (ATSDR) lists the possible health effects of PFAS.

PFAS health effects
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Evolving drinking water regulations

On April 10, 2024, EPA announced the final National Primary Drinking Water Regulation (NPDWR) to establish maximum contaminant levels (MCLs) for six PFAS in drinking water. The table below lists individual MCLs and MCL goals (MCLGs) along with a hazard index for PFAS mixtures.

Learn more at EPA
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Compound Final MCLG Final MCL (enforceable levels)
PFOA Zero 4.0 parts per trillion (ppt) (also expressed as ng/L)
PFOS Zero 4.0 ppt
PFHxS 10 ppt 10 ppt
PFNA 10 ppt 10 ppt
HFPO-DA (commonly known as GenX Chemicals) 10 ppt 10 ppt
Mixtures containing two or more of PFHxS, PFNA, HFPO-DA, and PFBS

1 (unitless)

Hazard Index

1 (unitless)

Hazard Index

The final rule requires:

  • Public water systems must monitor for these PFAS and have three years to complete initial monitoring (by 2027), followed by ongoing compliance monitoring. Water systems must also provide the public with information on the levels of these PFAS in their drinking water beginning in 2027.
  • Public water systems have five years (by 2029) to implement solutions that reduce these PFAS if monitoring shows that drinking water levels exceed these MCLs.
  • Beginning in five years (2029), public water systems that have PFAS in drinking water which violates one or more of these MCLs must take action to reduce levels of these PFAS in their drinking water and must provide notification to the public of the violation. 

Our results

The Safe Drinking Water Act requires that every five years the Environmental Protection Agency (EPA) issue a list of unregulated contaminants to be monitored by public water systems, known as the Unregulated Contaminant Monitoring Rule (UCMR). Unregulated contaminants do not have an EPA-established maximum contaminant level designated. The latest UCMR (UCMR 5) requires analysis for 29 PFAS compounds between 2023 and 2025.

In June 2023, Toho began sampling for UCMR 5 (29 PFAS compounds) and will complete sampling by January 2025. The results so far are published below. As others are completed, they will be posted here. If any unregulated contaminants are detected, they will also be reported in our annual water quality reports.

Our results
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Learn more about Toho’s water quality

Toho actively monitors our water sources to ensure the water we serve follows all state and federal drinking water health standards.

PFAS and wastewater

Toho treats all of the community’s wastewater turning it into reclaimed water. PFAS compounds are difficult to break down and currently there are no viable options for removing PFAS from wastewater and biosolids. The best way to remove PFAS from wastewater is to prevent them from entering the sewer system to begin with and to use PFAS-free products.

Image of wastewater treatment facility.

What can you do?

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