PFAS · Maryland

PFAS in Maryland drinking water: EPA’s final survey results

EPA’s national PFAS survey (UCMR 5) tested 76 of the community water systems that serve homes in Maryland. 26 found at least one of 29 PFAS above the laboratory reporting level, and 13 had a PFOA or PFOS sampling-location yearly average at or above EPA’s 4.0 ppt limit. Samples were collected from January 2023 to May 2026.

In focus34%of surveyed systems found PFAS

Public records. Clearer context.

Data as of EPA UCMR 5 final release, August 2026 (file dated Aug 28, 2026) · EPA SDWIS 2026Q2 (file dated Jul 9, 2026). How we build these pages

Maryland community systems in EPA’s survey

serving about 5,327,587 people

found at least one PFAS

34% of surveyed systems; about 4,276,396 people served

PFOA or PFOS yearly average at or above the MCL

compared the way EPA does: the average of a complete sampling set

lithium at or above EPA’s health reference level

lithium was part of the same survey

PFPeA was the compound Maryland community systems found most often: 22 of 76 tested systems measured it above the reporting level. Across the country, 35% of surveyed community systems found at least one PFAS; in Maryland the share is 34%. The largest Maryland system with a detection, Washington Suburban Sanitary Commission, serves 1,900,000 people and found 2 of the 29 compounds.

Which PFAS were found most often in Maryland

Each row counts the Maryland community water systems where that compound was measured above the reporting level at least once. A detection is a measurement, not a violation: most of these compounds have no federal limit.

Compound	Systems where found	Systems tested	Share
PFPeA	22	76	29%
PFHxA	18	76	24%
PFBS	16	76	21%
PFHxS	14	76	18%
PFOA	13	76	17%
PFBA	12	76	16%
PFOS	12	76	16%
PFHpA	9	76	12%
6:2 FTS	1	76	1%

Maryland systems with the most PFAS found

The 10 surveyed community water systems that found the most different PFAS, with PFOA and PFOS compared to EPA’s 4.0 ppt limits on the yearly average at the highest sampling location. Larger systems come first when counts tie.

Water system	People served	PFAS found (of 29)	PFOA	PFOS
Maryland American Water Company MD0120003	13,200	9	7.6 ppt at or above the MCL	7.3 ppt at or above the MCL
City of Westminster MD0060015	35,256	8	11.4 ppt at or above the MCL	6.6 ppt at or above the MCL
City of Aberdeen MD0120001	18,006	8	7.4 ppt at or above the MCL	8.2 ppt at or above the MCL
Town of Elkton MD0070011	15,625	8	22.7 ppt at or above the MCL	7.1 ppt at or above the MCL
Town of Hampstead MD0060003	6,600	8	9.0 ppt at or above the MCL	5.5 ppt at or above the MCL
Town of Poolesville MD0150002	6,005	8	5.3 ppt at or above the MCL	6.1 ppt at or above the MCL
Town of Middletown MD0100018	4,288	8	4.9 ppt at or above the MCL	6.4 ppt at or above the MCL
Town of Mount Airy MD0060007	9,890	7	8.5 ppt at or above the MCL	6.0 ppt at or above the MCL
City of Salisbury MD0220004	30,343	6	2.9 ppt below the MCL	10.0 ppt at or above the MCL
City of Taneytown MD0060012	6,750	6	4.4 ppt at or above the MCL	10.4 ppt at or above the MCL

Counties with the most systems that found PFAS

Carroll County 6 of 6 surveyed systems
Frederick County 5 of 7 surveyed systems
Montgomery County 3 of 3 surveyed systems
Harford County 2 of 5 surveyed systems
Worcester County 2 of 5 surveyed systems
Cecil County 2 of 4 surveyed systems
Wicomico County 2 of 3 surveyed systems
Baltimore city 1 of 1 surveyed systems

How to read these numbers

UCMR 5 asked every community and non-transient non-community water system serving 3,300 or more people, and a sample of smaller ones, to test for 29 PFAS and lithium. EPA published the final data in August 2026; its samples were collected from January 2023 to June 2026. A system that was not in the survey has no result here; that is not the same as having no PFAS.

UCMR 5 is a one-time national monitoring survey. Its results do not indicate compliance or non-compliance with the PFAS Maximum Contaminant Levels, which are enforced on running annual averages and take effect in 2029 (EPA has proposed allowing extensions to 2031). A single result above a limit on this page is a measurement, not a violation.

See how to read UCMR 5 results and our methodology for how systems are matched to places.

After Maryland’s PFAS results

Find your system. Then read its report.

State recordsAll Maryland water recordsCounties, ZIP reports, lead results and violations for the whole state.FiltersChoosing a PFAS filterHow to check a filter’s certified PFAS reduction before you buy.Your utilityFind your annual water reportYour utility’s Consumer Confidence Report will list its own PFAS results and any treatment plans.

County pages

Maryland water records

Sources

EPA UCMR 5 occurrence data, samples collected 2023-01-03 – 2026-06-17, final release, August 2026 (file dated Aug 28, 2026); EPA SDWIS via ECHO, 2026Q2 extract (file dated Jul 9, 2026); EPA service-area boundaries v3.0; Census 2020 ZCTAs. Database prepared 2026-09-03.