Maryland Department of the Environment

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PFAS in Maryland's Drinking Water

​​Maryland is taking a science-based approach to understanding and reducing the risk of PFAS exposure to Marylanders. 

This page describes Maryland's actions to address PFAS in drinking water.

​​As information and data on PFAS continues to evolve, the following section provides an overview of each phase from our statewide PFAS in Public Drinking Water Study. 


PFAS in Drinking Water Study:​​

​In 2020, MDE-WSP began its multi-phase PFAS in Public Drinking Water Study in collaboration with the MDH-Laboratories Administration (MDH-LA)​​. This study began as a way to help MDE understand the prevalence of PFAS contamination in its Public Water Systems (PWS) statewide. MDE-WSP is using this data to help water systems develop a plan for addressing PFAS in their systems with the goal that all Public Water Systems be in compliance with the PFAS Maximum Contaminant Levels (MCLs) by their effective date. In 2022, MDE completed sampling its Community Water Systems (CWS). We are currently in Phase 5 of our PFAS in Public Drinking Water ​​Study.


Below is an interactive map of all publicly available sampling results from this study. If you would like to review this map and its features in its entirety, please visit the webpage linked here.​

​​Below are links to our individual phase reports:

  • Phase 1
    • ​In September 2020, MDE initiated Phase 1 of the PFAS study to evaluate the occurrence of PFAS in PWS. During this phase, 129 Community Water Systems Water Treatment Plants (CWS-WTPs) were sampled and tested for all 18 PFAS analytes under EPA Method 537.1. Under Phase 1, approximately 13% of Maryland's federally regulated CWS's were monitored.
    • Data (Excel ​or PDF)
  • Phase 2
    • ​​As a result of the findings from Phase 1, MDE continued with Phase 2 of its PWS study from March through May 2021. Under Phase 2, 159 initial groundwater samples and eight (8) initial point of entry samples were collected. Under Phase 2, approximately 14% of Maryland's federally regulated CWS's were monitored.
    • ​Data (Excel or PDF)
  • Phase 3
    • ​In August 2021, MDE initiated the third phase of its PWS study to evaluate the occurrence​​ of PFAS in drinking water. During this phase, 759 drinking water samples were collected and tested for 18 PFAS under EPA Method 537.1. Samples collected under Phase 3 consisted of both finished and untreated water from a variety of groundwater sources withdrawing from confined, semi-confined, and unconfined aquifers, springs, and one surface water source.
    • Data (Excel or PDF)
  • Phase 4
    • ​On June 15, 2022, the EPA released interim health advisories for PFOA and PFOS in drinking water at 0.004 parts per trillion (ppt) and 0.02 ppt, respectively. In response to these lowered levels, MDE initiated Phase 4 sampling, which looked at CWS's with previous detections of PFOA and PFOS (during Phases 1 through 3).​
    • Data (Excel or PDF) 
  • Phase 5 - Report in Progress​
    • In 2023, MDE initiated Phase 5 sampling which included Non-Transient Non-Community (NTNC) water systems. Sampling was completed in January 2025.
If you would like more information about these reports please contact the Water Supply Program at water.supply@maryland.gov.


Click on the below dropdowns for more information on PFAS in Drinking Water.​

What are PFAS

 
Per- and polyfluoroalkyl substances (PFAS) are a group of man-made chemicals that include PFOA, PFOS, PFHxS, GenX, and many other chemical compounds. PFAS have been manufactured and used in a variety of industries around the globe, including in the United States since the 1940s. These chemicals are persistent in the environment and the human body, meaning they do not break down easily and can accumulate over time.

The Finalized EPA Rule

 
Under the Safe Drinking Water Act, on April 10, 2024, EPA announced the final National Primary Drinking Water Regulation (NPDWR) establishing legally enforceable levels, called Maximum Contaminant Levels (MCLs), for six PFAS compounds in drinking water. Under EPA's new regulations, Non-Transient Non-Community (NTNC) and Community Water Systems (CWS) will be regulated.

Below is a breakdown for individual EPA MCLs:
PFAS_MCLs2.PNG

Rule Requirements for Public Water Systems

 
Initial Monitoring:

All NTNC and CWS must complete initial PFAS monitoring by 2027. This initial monitoring requirement is based on the system source and size as follows: 

MonitoringRequirements2.PNG

Samples are required to be taken at all entry points to the distribution system and required to be analyzed using either EPA Method 533 or 537.1. To reduce costs, MDE will allow systems to use previously collected PFAS sampling results to satisfy some or all of the initial monitoring requirements.

A list of labs that test in Maryland​​ for PFAS in drinking water can be found here.

For more information on PFAS lab certifications please visit the Maryland Drinking Water Lab Certification Program webpage linked here.

Ongoing Compliance Monitoring:

In 2023, MDE began requiring Community Water Systems (CWS) to report PFAS results in their annual Consumer Confidence Reports (CCR). Starting in April 2027, per EPA regulations, all systems will be required to report these results to their consumers and issue public notices for any monitoring or sampling procedure violations. Starting in April 2029, systems must comply with all regulated PFAS MCLs and will be required to issue public notices for MCL violations.

For additional information, please see the below Fact Sheet:

Remediation For Public Water Systems

 

MDE's WSP is working with water systems to develop and implement remediation plans. This may involve adding treatment, interconnections with nearby systems, or drilling new wells.


The following treatment options were identified by the EPA as the Best Available Technologies (BATs) for meeting the PFAS MCLs:

BATsTable2.PNG

For further information on these Best Available Technologies:

Funding for Public Water Systems

 
The Maryland Department of the Environment (MDE) is receiving grant funding through the Bipartisan Infrastructure Law (BIL). Funding is received through the BIL Drinking Water State Revolving Fund (DWSRF) and the BIL Small and Disadvantaged Communities Grant Programs. Funding is available​ for projects addressing PFAS. The funding solicitation period generally runs from early December to January 31st of the following year. For more information about funding and for technical assistance, reach out to MDE-WSP at water.supply@maryland.gov or visit the Maryland Water Infrastructure Financing Administration website linked here.
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Private Well Owner Resources

 

Below is a link to our Fact Sheet with helpful information for homeowners on a private well:

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PFAS in Private Drinking Water Wells​​​


The quality and safety of drinking water from private domestic wells are not regulated under the Safe Drinking Water Act. It is the responsibility of the individual homeowner to test and maintain​ their well and piping. For any questions regarding your private well please contact your county health department.

For questions regarding PFAS and your health, please contact the Maryland Department of Health at 410-767-6802.
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Additional Fact Sheets and Links

Maryland Department of the Environment
1800 Washington Blvd
Baltimore, MD 21230