Systems with a yearly average at or above an EPA-based study benchmark
16.9%12 of 71 active community water systems
All 71 systems had enough required samples to calculate a yearly average. 12 had at least one yearly average at or above a study benchmark; 59 did not.
EPA-based study benchmark: the unrounded cutoff this research uses to reproduce EPA’s January 2026 technical-assistance classification around the April 2024 federal levels. It is not a current standard or compliance finding and cannot determine household exposure or health risk.
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ZIP codes are used only to route visitors to public water systems that reported serving them. Confirm the actual provider using a water bill or utility record.
Compound summary
System counts in Maryland
Each count shows how many included water systems had a yearly average at or above the named study benchmark.
| Study benchmark | Systems at or above benchmark | Water systems included | Percent |
|---|---|---|---|
| PFOA: 4.05 ppt study benchmark (reproduces EPA classification around 4 ppt) | 11 | 71 | 15.5% |
| PFOS: 4.05 ppt study benchmark (reproduces EPA classification around 4 ppt) | 10 | 71 | 14.1% |
| PFHxS: 15 ppt study benchmark (reproduces EPA classification around 10 ppt) | 0 | 71 | 0.0% |
| PFNA: 15 ppt study benchmark (reproduces EPA classification around 10 ppt) | 0 | 71 | 0.0% |
| HFPO-DA: 15 ppt study benchmark (reproduces EPA classification around 10 ppt) | 0 | 71 | 0.0% |
| Hazard Index: 1.5 study benchmark with at least two detected components (reproduces EPA classification around 1) | 0 | 71 | 0.0% |
System directory
Community water systems with complete monitoring
“Complete monitoring” means at least one sampling location had all required samples needed for a yearly average. Each PWSID appears once, preventing double counting across ZIP associations.
| Public water system | PWSID | Population served | Primary source | Sampling locations | Study benchmark result |
|---|---|---|---|---|---|
| BOONSBORO - KEEDYSVILLE | MD0210002 | 4,250 | Surface water | 3 | At or above a study benchmark |
| BROAD CREEK | MD0020004 | 26,033 | Ground water | 1 | Below all study benchmarks |
| BRYANS ROAD | MD0080033 | 6,260 | Ground water | 4 | Below all study benchmarks |
| CHAPEL HILL - ABERDEEN PROVING GROUNDS | MD0120002 | 15,000 | Ground water | 1 | Below all study benchmarks |
| CHARLOTTE HALL VA HOME | MD0180217 | 270 | Ground water | 1 | Below all study benchmarks |
| CHESAPEAKE RANCH ESTATES | MD0040004 | 9,500 | Ground water | 4 | Below all study benchmarks |
| CITY OF ABERDEEN | MD0120001 | 18,006 | Surface water purchased | 2 | At or above a study benchmark |
| CITY OF ANNAPOLIS | MD0020001 | 35,000 | Ground water | 1 | Below all study benchmarks |
| CITY OF BALTIMORE | MD0300002 | 1,600,000 | Surface water | 3 | Below all study benchmarks |
| CITY OF BOWIE, MD | MD0160002 | 25,000 | Ground water | 1 | Below all study benchmarks |
| CITY OF BRUNSWICK | MD0100005 | 7,312 | Surface water | 2 | Below all study benchmarks |
| CITY OF CAMBRIDGE | MD0090002 | 15,000 | Ground water | 4 | Below all study benchmarks |
| CITY OF CUMBERLAND | MD0010008 | 27,039 | Surface water | 1 | Below all study benchmarks |
| CITY OF FREDERICK | MD0100015 | 54,000 | Surface water | 4 | Below all study benchmarks |
| CITY OF FROSTBURG | MD0010011 | 11,000 | Surface water | 1 | Below all study benchmarks |
| CITY OF HAGERSTOWN | MD0210010 | 92,200 | Surface water | 1 | Below all study benchmarks |
| CITY OF HAVRE DE GRACE | MD0120012 | 14,000 | Surface water | 1 | Below all study benchmarks |
| CITY OF POCOMOKE CITY | MD0230006 | 4,100 | Ground water | 1 | Below all study benchmarks |
| CITY OF ROCKVILLE | MD0150003 | 52,000 | Surface water | 1 | Below all study benchmarks |
| CITY OF SALISBURY | MD0220004 | 30,343 | Ground water | 2 | At or above a study benchmark |
| CITY OF TANEYTOWN | MD0060012 | 6,750 | Ground water | 7 | At or above a study benchmark |
| CITY OF WESTMINSTER, MD | MD0060015 | 35,256 | Surface water | 10 | At or above a study benchmark |
| CROFTON-ODENTON | MD0020008 | 62,986 | Ground water | 1 | Below all study benchmarks |
| EASTERN CORRECTIONAL INSTITUTE | MD0190013 | 3,500 | Ground water | 1 | Below all study benchmarks |
| EASTERN REGION ALLEGANY DISTRIB. SYSTEM | MD0010005 | 5,703 | Surface water purchased | 1 | Below all study benchmarks |
| EASTON UTILITIES | MD0200003 | 17,357 | Ground water | 4 | Below all study benchmarks |
| ELKTON WEST | MD0070015 | 3,500 | Surface water purchased | 1 | Below all study benchmarks |
| FORT GEORGE G. MEADE | MD0020012 | 62,234 | Ground water | 1 | Below all study benchmarks |
| FREEDOM DISTRICT | MD0060002 | 24,867 | Surface water | 1 | Below all study benchmarks |
| GLEN BURNIE-BROADNECK | MD0020017 | 290,606 | Ground water | 4 | Below all study benchmarks |
| HARFORD COUNTY D.P.W. | MD0120016 | 104,567 | Surface water | 3 | Below all study benchmarks |
| HOWARD COUNTY D.P.W. DISTRIBUTION | MD0130002 | 286,158 | Surface water purchased | 2 | Below all study benchmarks |
| LAVALE SANITARY COMMISSION | MD0010016 | 5,500 | Surface water purchased | 2 | Below all study benchmarks |
| LEXINGTON PARK | MD0180007 | 43,030 | Ground water | 2 | Below all study benchmarks |
| MARYLAND AMERICAN WATER COMPANY | MD0120003 | 13,200 | Surface water | 2 | At or above a study benchmark |
| MIDLAND-LONACONING | MD0010018 | 5,000 | Surface water | 2 | Below all study benchmarks |
| MYSTIC HARBOUR | MD0230011 | 5,945 | Ground water | 4 | Below all study benchmarks |
| NAVAL SUPPORT FACILITY, INDIAN HEAD | MD0080058 | 3,321 | Ground water | 4 | Below all study benchmarks |
| NEW DESIGN - FREDERICK COUNTY | MD0100030 | 74,911 | Surface water | 1 | Below all study benchmarks |
| OCEAN PINES | MD0230005 | 11,890 | Ground water | 5 | Below all study benchmarks |
| PATUXENT NAVAL AIR STATION (NAVFAC-WASH) | MD0180022 | 22,000 | Ground water | 13 | Below all study benchmarks |
| PINEY POINT | MD0180034 | 672 | Ground water | 1 | Below all study benchmarks |
| PRINCE FREDERICK | MD0040011 | 4,371 | Ground water | 2 | Below all study benchmarks |
| SEVERN WATER COMPANY | MD0020027 | 5,447 | Ground water | 1 | Below all study benchmarks |
| SOLOMONS | MD0040027 | 3,811 | Ground water | 2 | Below all study benchmarks |
| STEVENSVILLE | MD0170019 | 9,155 | Ground water | 6 | Below all study benchmarks |
| THE PROVINCES | MD0020029 | 3,991 | Ground water | 1 | Below all study benchmarks |
| TOWN OF BERLIN | MD0230001 | 4,500 | Ground water | 3 | Below all study benchmarks |
| TOWN OF CENTREVILLE | MD0170001 | 3,322 | Ground water | 2 | Below all study benchmarks |
| TOWN OF CHESAPEAKE BEACH | MD0040003 | 5,000 | Ground water | 3 | Below all study benchmarks |
| TOWN OF CHESTERTOWN | MD0140002 | 5,400 | Ground water | 1 | Below all study benchmarks |
| TOWN OF DELMAR | MD0220001 | 4,500 | Ground water | 1 | Below all study benchmarks |
| TOWN OF ELKTON | MD0070011 | 15,625 | Surface water | 5 | At or above a study benchmark |
| TOWN OF HAMPSTEAD | MD0060003 | 6,600 | Ground water | 10 | At or above a study benchmark |
| TOWN OF HANCOCK | MD0210012 | 1,921 | Ground water | 1 | Below all study benchmarks |
| TOWN OF INDIAN HEAD | MD0080020 | 4,100 | Ground water | 3 | Below all study benchmarks |
| TOWN OF LA PLATA | MD0080025 | 11,535 | Ground water | 5 | Below all study benchmarks |
| TOWN OF MANCHESTER | MD0060006 | 4,954 | Ground water | 11 | At or above a study benchmark |
| TOWN OF MILLINGTON | MD0140010 | 625 | Ground water | 1 | Below all study benchmarks |
| TOWN OF MOUNT AIRY | MD0060007 | 9,890 | Ground water | 5 | At or above a study benchmark |
| TOWN OF NORTH EAST | MD0070016 | 8,600 | Surface water | 2 | Below all study benchmarks |
| TOWN OF OCEAN CITY | MD0230003 | 30,000 | Ground water | 2 | Below all study benchmarks |
| TOWN OF PERRYVILLE | MD0070018 | 4,413 | Surface water | 1 | Below all study benchmarks |
| TOWN OF POOLESVILLE | MD0150002 | 6,005 | Groundwater under influence of surface water | 9 | At or above a study benchmark |
| TOWN OF PRINCESS ANNE | MD0190002 | 3,300 | Ground water | 7 | Below all study benchmarks |
| TOWN OF THURMONT | MD0100023 | 6,200 | Groundwater under influence of surface water | 3 | At or above a study benchmark |
| TOWN OF WALKERSVILLE | MD0100025 | 8,440 | Groundwater under influence of surface water | 1 | Below all study benchmarks |
| U.S. NAVAL ACADEMY | MD0020042 | 8,700 | Ground water | 1 | Below all study benchmarks |
| WALDORF - CHARLES COUNTY DPW | MD0080049 | 84,296 | Surface water purchased | 18 | Below all study benchmarks |
| WASHINGTON SUBURBAN SANITARY COMMISSION | MD0150005 | 1,900,000 | Surface water | 2 | Below all study benchmarks |
| WHITE PLAINS 2 MHP/JACK BLAIR | MD0080208 | 70 | Ground water | 1 | Below all study benchmarks |
How the count works
What is included
Each active community water system with enough required samples for a yearly average is counted once, even if it is linked with several ZIP codes. This does not mean every home was tested. Private wells are excluded, and UCMR 5 did not comprehensively monitor every small system. This page does not apply Maryland's state-specific standards or determine compliance. Use the official state or territory drinking-water program for current regulatory information.