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  1. Select a site type.
    1. Drinking Water Sources
      • Choose a PFAS compound or group of compounds to color-code the map by concentration.
    2. Choose “Exceeding Maximum Contaminant Level” to display water sites where contaminants are above the PFAS National Primary Drinking Water Regulation guidelines.
    3. Deposition
      • Select wet deposition sites to see PFAS rainwater data.
      • Select dry deposition sites to see PFAS in free-falling particulate matter.
    4. Ambient Air
      • Select to see PFAS in air samples.
  2. Click on a site icon on the map or jump to a site to view PFAS data from that site.
  3. Select About this Graph to learn more about the data you are viewing.
In April 2024, the EPA announced final Maximum Contaminant Levels (MCLs) for six PFAS as part of the PFAS National Primary Drinking Water Regulation (NPDWR).

What is an MCL?

  • The highest level of a contaminant legally allowed in a drinking water source.
  • A guideline to minimize health risks based on peer-reviewed science and feasible implementation.
  • A quantity above which public water system will be required to reduce the amount of contaminant in their water.
Regulatory Levels: Summary
Chemical Maximum Contaminant Level Goal (MCLG) Maximum Contaminant Level (MCL)
PFOA 0 4.0 parts-per-trillion (ppt)
PFOS 0 4.0 ppt
PFNA 10 ppt 10 ppt
PFHxS 10 ppt 10 ppt
HFPO-DA 10 ppt 10 ppt
Mixtures containing two or more of PFNA, PFHxS, PFBS, HFPO-DA 1.0 (unitless) hazard index 1.0 (unitless) hazard index

Why are the PFOA and PFOS MCLGs different than MCLS?

  • MCLGs are non-enforceable health-based goals while MCLs are enforceable levels.
  • The EPA MCLGs of zero for PFOA and PFOS indicate that there is no level of exposure to these chemicals without risk of health impacts.
  • The PFOA and PFOS MCLs of 4.0 ppt represent the lowest level of these PFAS in our drinking water to reduce exposure that is feasible for effective implementation.

What if a site near me is above the MCL?

  • Please note that the data available on our website represents samples that were collected prior to the establishment of the MCLs.
  • Consider checking your local public utility page for more recent testing of your drinking water supply and updates on actions taken to reduce PFAS levels in your water.

PFAS Data Analysis Tool

Individuals who use data from the PFAS Testing Network website for use in any communication should consult the principal investigator about data use prior to publication, offer co-authorship or collaborator status in cases of significant contribution, and ensure proper citation and acknowledgement of funding in the final work. Please consult the Data Sharing and Use Policy for a complete description of data use guidelines.

Principal Investigators

  • Water Sites: Dr. Lee Ferguson and Dr. Detlef Knappe
  • Atmospheric and Ambient Air Sites: Dr. Ralph Mead, Dr. Jason Surratt, and Dr. Barbara Turpin