State drinking water records
Maryland drinking water systems
463 community water systems serve Maryland and are listed below under 24 counties and on the pages of 399 cities and towns. Their own population figures add up to 5,529,402 people, a sum that counts people twice where one system sells water to another.
158 of them (34%) had at least one health-based violation in the last 10 years. 38 systems still have one unresolved.
386 rely mainly on groundwater and 75 on surface water, counting water bought from other systems.
446 systems filed a lead service line inventory listing 261 lead lines, 3,018 galvanized lines that must be replaced and 564,412 lines of unknown material.
18 systems have no service area map from EPA and are placed by mailing address.
- Community water systems
- 463
- People served, sum of each system's own figure
- 5,529,402
- Systems with a health-based violation, last 10 years
- 158
- Systems with one unresolved
- 38
- Lead service lines in inventories
- 261
Counties
24 countiesEach county counts the systems whose service area map reaches it. Systems placed only by a mailing address are listed on the county pages but not counted here.
| County | Systems | People served | With a health-based violation, 10 years | With one unresolved |
|---|---|---|---|---|
| Allegany County | 17 | 65,734 | 6 | 3 |
| Anne Arundel County | 27 | 508,684 | 7 | 2 |
| Baltimore County | 6 | 1,600,760 | 4 | 1 |
| Baltimore city | 4 | 1,601,151 | 3 | 1 |
| Calvert County | 30 | 36,050 | 5 | 2 |
| Caroline County | 19 | 12,921 | 10 | 4 |
| Carroll County | 24 | 97,151 | 10 | 2 |
| Cecil County | 45 | 52,295 | 24 | 8 |
| Charles County | 48 | 119,546 | 6 | 3 |
| Dorchester County | 12 | 20,208 | 4 | 1 |
| Frederick County | 31 | 190,730 | 6 | 3 |
| Garrett County | 15 | 13,731 | 5 | 1 |
| Harford County | 17 | 168,724 | 7 | 0 |
| Howard County | 3 | 286,643 | 2 | 0 |
| Kent County | 11 | 11,390 | 4 | 1 |
| Montgomery County | 3 | 1,958,005 | 0 | 0 |
| Prince George's County | 5 | 1,926,410 | 2 | 0 |
| Queen Anne's County | 14 | 16,709 | 7 | 0 |
| Somerset County | 8 | 11,051 | 5 | 0 |
| St. Mary's County | 38 | 91,164 | 6 | 0 |
| Talbot County | 8 | 22,760 | 4 | 1 |
| Washington County | 20 | 111,038 | 6 | 2 |
| Wicomico County | 24 | 47,277 | 13 | 1 |
| Worcester County | 19 | 61,238 | 9 | 0 |
Largest systems
| System | Main county | People served | Main source | Health-based violations, 10 years | Unresolved | Lead lines |
|---|---|---|---|---|---|---|
| Washington Suburban Sanitary Commission | Prince George's County and 1 other county | 1,900,000 | Surface water | 0 | 0 | 8 |
| City of Baltimore | Baltimore County and 1 other county | 1,600,000 | Surface water | 1 | 0 | 47 |
| Glen Burnie-Broadneck | Anne Arundel County | 290,606 | Groundwater | 0 | 0 | 0 |
| Howard County D.P.W. Distribution | Howard County | 286,158 | Purchased surface water | 0 | 0 | 0 |
| Harford County D.P.W. | Harford County | 104,567 | Surface water | 0 | 0 | 0 |
| City of Hagerstown | Washington County | 92,200 | Surface water | 0 | 0 | 0 |
| Waldorf - Charles County DPW | Charles County | 84,296 | Purchased surface water | 0 | 0 | 0 |
| New Design - Frederick County | Frederick County | 74,911 | Surface water | 0 | 0 | 0 |
| Crofton-Odenton | Anne Arundel County | 62,986 | Groundwater | 0 | 0 | 0 |
| Fort George G. Meade | Anne Arundel County | 62,234 | Groundwater | 0 | 0 | 0 |
| City of Frederick | Frederick County | 54,000 | Surface water | 0 | 0 | 20 |
| City of Rockville | Montgomery County | 52,000 | Surface water | 0 | 0 | 0 |
| Lexington Park | St. Mary's County | 43,030 | Groundwater | 0 | 0 | 0 |
| City of Westminster | Carroll County | 35,256 | Surface water | 4 | 0 | 0 |
| City of Annapolis | Anne Arundel County | 35,000 | Groundwater | 0 | 0 | 0 |
Systems with unresolved health-based violations
38 systems| System | Main county | People served | Main source | Health-based violations, 10 years | Unresolved | Lead lines |
|---|---|---|---|---|---|---|
| Tebbston on Magothy | Anne Arundel County | 52 | Groundwater | 5 | 5 | 0 |
| Barrelville | Allegany County | 130 | Groundwater | 1 | 4 | No inventory |
| Du Mar Estates Water Company | Charles County | 150 | Groundwater | 1 | 3 | 0 |
| Swann Haven Mobile Home Park | Talbot County | 44 | Groundwater | 1 | 3 | No inventory |
| Gaither Manor Apartments | Carroll County | 450 | Groundwater | 1 | 2 | No inventory |
| West Nottingham Academy | Cecil County | 250 | Groundwater | 2 | 2 | 0 |
| The Neighborhoods at St. Elizabeth | Baltimore city | 162 | Purchased surface water | 1 | 2 | 0 |
| Thunderbird Motel | Charles County | 60 | Groundwater | 1 | 2 | 0 |
| Western Region Allegany Distrib. System | Allegany County | 4,955 | Purchased surface water | 0 | 1 | 0 |
| Elkton West | Cecil County | 3,500 | Purchased surface water | 1 | 1 | 0 |
| Town of Westernport | Allegany County | 2,200 | Surface water | 2 | 1 | 0 |
| Town of Rock Hall | Kent County | 1,750 | Groundwater | 0 | 1 | 0 |
| Holiday Mobile Estates, Inc. | Anne Arundel County | 900 | Groundwater | 1 | 1 | 0 |
| Town of Cecilton | Cecil County | 477 | Groundwater | 3 | 1 | 0 |
| The Calverton School | Calvert County | 461 | Groundwater | 1 | 1 | 0 |
| Cecil Woods M.H.P. Distribution System | Cecil County | 320 | Purchased groundwater | 1 | 1 | 0 |
| Cedar Mobile Home Park | Caroline County | 300 | Groundwater | 2 | 1 | 0 |
| Beaver Run Mobile Home Park | Dorchester County | 275 | Groundwater | 1 | 1 | 0 |
| Aqualand Campground | Charles County | 240 | Groundwater | 0 | 1 | 0 |
| Regency Manor Mobile Home Park | Calvert County | 224 | Groundwater | 1 | 1 | 0 |
| Sandy Hook | Washington County | 220 | Groundwater | 0 | 1 | 0 |
| Town of Henderson | Caroline County | 156 | Groundwater | 0 | 1 | 0 |
| Concord Estates Mobile Home Park | Frederick County | 150 | Groundwater | 1 | 1 | 0 |
| Golden Kay Apartments | Cecil County | 148 | Groundwater | 5 | 1 | 0 |
| Chapel Hill Nursing Center | Baltimore County | 125 | Groundwater | 2 | 1 | 0 |
| Tranquility at Fredericktowne | Frederick County | 105 | Purchased surface water | 1 | 1 | 0 |
| Harbour Light Estates Community | Wicomico County | 95 | Groundwater | 1 | 1 | 0 |
| Lakeview MHP LLC | Carroll County | 76 | Groundwater | 0 | 1 | 0 |
| Deep Roots Inc. | Cecil County | 60 | Groundwater | 1 | 1 | 0 |
| Cecilton Manor Mobile Home Park | Cecil County | 60 | Groundwater | 0 | 1 | 0 |
| Garden Estates Central Water | Charles County | 55 | Groundwater | 1 | 1 | No inventory |
| Woodlawn Mobile Home Park - Old | Cecil County | 50 | Groundwater | 0 | 1 | 0 |
| Cedar Ridge Children's Home & School | Washington County | 45 | Groundwater under direct influence | 0 | 1 | 0 |
| Liberty Mobile Home Park | Caroline County | 40 | Groundwater | 4 | 1 | 0 |
| Amelano Manor | Frederick County | 36 | Groundwater | 1 | 1 | 0 |
| White Oak Mobile Home Park | Garrett County | 32 | Groundwater | 1 | 1 | 0 |
| Taylors Mobile Home Park | Caroline County | 27 | Groundwater | 1 | 1 | 0 |
| Graymount Apartments | Cecil County | 27 | Groundwater | 1 | 1 | 0 |
Counties come from the counties EPA lists each system serving, matched to 2024 Census counties; where EPA lists none, from the county coded in the system's ID, its service area map, or its mailing address. A county holding at least a fifth of a system's service area map is added when at least a fifth of that map lies in those counties. Towns are the ones EPA lists and the Census places such a map covers, always inside those counties. In New England, where EPA's town names a whole Town, it is not matched to the village of the same name. A system is not listed in a county holding less than a fifth of its map, or in a county or town its map reaches when the map lies mostly outside the counties EPA lists, so a page can leave out a system that serves part of the area. Methodology and limitations