The Power of Information

National Drinking Water Database


478 systems serving 5,156,372 people

This drinking water quality report shows results of tests conducted by water utilities in Maryland, provided to the Environmental Working Group (EWG) by the Maryland Department of Environment. It is part of EWG's national database that includes 47,667 drinking water utilities and 20 million test results from 45 states and the District of Columbia. Water utilities nationwide detected more than 300 pollutants between 2004 and 2009. More than half of these chemicals are unregulated, legal in any amount. Despite this widespread contamination, the federal government invests few resources in protecting rivers, reservoirs, and groundwater from pollution in the first place. The information below summarizes drinking water quality for this state.

Water Utilities
Population Served
Detected Chemicals
Exceed health guidelines*
Exceed Legal Limits*
Unregulated chemicals detected
* Water utilities are noted as exceeding the legal limit if any test is above the maximum contaminant level (MCL). Most MCLs are based on annual averages so exceeding the MCL for one test does not necessarily indicate that the system is out of compliance.

50 Contaminants Exceeding Health Based Limits

Contaminants detected in Maryland drinking water above health guidelines, according to an Environmental Working Group analysis of data obtained from state water authorities

Number of Systems
At Any Level Above Health Limits At Any Level Above Health Limits
Total haloacetic acids (HAAs)5,020,6235,013,963251232
Dichloroacetic acid4,966,1814,966,181174174
Total trihalomethanes (TTHMs)5,116,2574,815,049371156
Di(2-ethylhexyl) phthalate4,785,0764,785,076308308
Alpha particle activity (excl radon and uranium)4,301,5614,301,561168168
Trichloroacetic acid4,907,6024,132,30220940

Water Utilities in Maryland Reporting Chemicals Exceeding Health Guidelines

Water utilities in Maryland reporting chemicals exceeding health guidelines, according to an Environmental Working Group analysis of data obtained from state water authorities, include:

Chemicals tested
Chemicals found
Chemicals exceeding
health guidelines
Luke / Newpage Luke Mill1841204223
City of Aberdeen14,5001263020
City of Westminster33,2781233117
Town of Poolesville5,1001232515
Harford County D.P.W.104,5671262215
City of Rockville46,5001192414
Town of Elkton12,4581242614
City of Taneytown6,7501232714
Town of Hampstead6,0621232814
Glen Burnie-Broadneck249,6001182214
Baltimore City Department of Public Works1,600,0001252213
Washington Suburban Sanitary Commission1,800,0001263113
A.P.G. Edgewood Arsenal6,2001262213
Town of Mount Airy8,6311212013
Town of Manchester4,0001262513
Crownsville State Hospital1,5861101613

Sources of Maryland Drinking Water Contaminants

The contaminants identified in Maryland drinking water come from a wide variety of sources, including agriculture, industry, water treatment plants, and polluted storm runoff from urban areas.

93Total Contaminants Detected (2004 - 2007)
35Agricultural Pollutants
(pesticides, fertilizer, factory farms)

Arsenic (total), Cyanide, Nitrate, Nitrite, Selenium (total), Endrin, Lindane, Methoxychlor, Dalapon, Simazine, Picloram, Dinoseb, Aldicarb sulfoxide, Metolachlor, Atrazine, Alachlor (Lasso), Heptachlor, 3-Hydroxycarbofuran, Heptachlor epoxide, Dieldrin, Butachlor, Propachlor, 2,4-D, 2,4,5-TP (Silvex), 2,4,5-T, Aldrin, Dicamba, Metribuzin, 1,2-Dibromo-3-chloropropane (DBCP), Ethylene dibromide (EDB), Chlordane, p-Dichlorobenzene, Monochlorobenzene (Chlorobenzene), Ethylbenzene, Perchlorate

26Sprawl and Urban Pollutants
(road runoff, lawn pesticides, human waste)

Nitrate, Copper, Lead (total), Arsenic (total), Tetrachloroethylene, MTBE, Nitrite, Xylenes (total), Dalapon, Cadmium (total), Antimony (total), Mercury (total inorganic), Dichloromethane (methylene chloride), Cyanide, o-Xylene, Benzene, p-Dichlorobenzene, Di(2-Ethylhexyl) adipate, 2,4-D, p-Xylene, m-Xylene, Chlordane, Benzo[a]pyrene, Lindane, 2,4,5-TP (Silvex), 2,4,5-T

51Industrial Pollutants

Aluminum, Arsenic (total), Barium (total), Cadmium (total), Chromium (total), Cyanide, Lead (total), Manganese, Mercury (total inorganic), Nitrate, Nitrite, Selenium (total), Antimony (total), Beryllium (total), Thallium (total), Lindane, p-Isopropyltoluene, Di(2-Ethylhexyl) adipate, Di(2-ethylhexyl) phthalate, Hexachlorocyclopentadiene, Chloromethane, MTBE, Hexachlorobenzene (HCB), Pentachlorophenol, cis-1,2-Dichloroethylene, Dichlorobiphenyl, Ethylene dibromide (EDB), Xylenes (total), p-Xylene, Dichloromethane (methylene chloride), p-Dichlorobenzene, 1,1-Dichloroethylene, 1,2-Dichloroethane, 1,1,1-Trichloroethane, Carbon tetrachloride, Trichloroethylene, Tetrachloroethylene, Monochlorobenzene (Chlorobenzene), Benzene, Toluene, Ethylbenzene, Isopropylbenzene, m-Xylene, o-Xylene, Alpha particle activity (excl radon and uranium), Combined Radium (-226 & -228), Radium-226, Radium-228, Perchlorate, Combined Uranium (pCi/L), Gross beta particle activity (pCi/L)

17Water Treatment and Distribution Byproducts
(pipes and fixtures, treatment chemicals and byproducts)

Total trihalomethanes (TTHMs), Total haloacetic acids (HAAs), Chloroform, Bromodichloromethane, Dibromochloromethane, Dichloroacetic acid, Trichloroacetic acid, Bromoform, Dibromoacetic acid, Monochloroacetic acid, Bromochloroacetic acid, Monobromoacetic acid, Di(2-ethylhexyl) phthalate, Cadmium (total), Chloromethane, Benzo[a]pyrene, Chlorodibromoacetic acid

20Naturally Occurring
(naturally present but increased for lands denuded by sprawl, agriculture, or industrial development)

Nitrate, Copper, Barium (total), Lead (total), Arsenic (total), Manganese, Radium-228, Radium-226, Alpha particle activity (excl radon and uranium), Combined Radium (-226 & -228), Gross beta particle activity (pCi/L), Combined Uranium (pCi/L), Chromium (total), Aluminum, Selenium (total), Nitrite, Radon, Mercury (total inorganic), Chloromethane, Cyanide

22Unregulated Contaminants
EPA has not established a maximum legal limit in tapwater for these contaminants

Lead (total), p-Isopropyltoluene, Aldicarb sulfoxide, Metolachlor, 3-Hydroxycarbofuran, Dieldrin, Butachlor, Propachlor, 2,4,5-T, Chloromethane, MTBE, Aldrin, Dichlorobiphenyl, Dicamba, Bromochloroacetic acid, Metribuzin, Isopropylbenzene, Radon, Perchlorate, Chlorodibromoacetic acid, Uranium-234 (pCi/L), Uranium-238 (pCi/L)

Testing Summary for Maryland

The federal government has set standards for some of the pollutants found in tap water supplies.

Contaminants reported as tested by water suppliers in Maryland141
 Contaminants tested due to federal law: 85
 Contaminants tested in addition to those required by federal law: 56

Violation Summary for Maryland

Data from the U.S. Environmental Protection Agency includes the following violations of federal standards in Maryland since 2004

Violation TypeNumber of Violations
Failure to monitor, Routine Major (Coliform bacteria)518
Failure to monitor regularly227
Failure to report information to the public or state agency in the Consumer Confidence Report207
Over maximum contaminant level, Average126
Follow-up and Routine Tap Sampling116
Maximum contaminant level, Monthly (Coliform bacteria)68
Monitoring and Reporting Disinfection Byproduct Rule24
Initial Tap Sampling for Lead and Copper12
Failure to monitor, Repeat Major (Coliform bacteria)10
Excess Turbidity at 0.3 NTU9
Failure to monitor, Repeat Minor (Coliform bacteria)8
Public Education7
Optimal Corrosion Control Treatment Study Recommendation7
Initial, Follow-up, or Routine Source Water Treatment Monitoring and Reporting6
Over maximum contaminant level, Single Sample5
Failure to monitor, Routine Minor (Coliform bacteria)5
Treatment Technique (Surface Water Treatment Rule)5
Excess Turbidity at 1 NTU5
Inadequate reporting of information to the public4
Maximum contaminant level, Acute (Coliform bacteria)4
Initial Water Quality Parameter Monitoring and Reporting4
Failure to notify public of violation3
Filter Turbidity Reporting3
Failure to Filter (Surface Water Treatment Rule)3
Failure to monitor or report, Routine/Repeat (Indicators of microbial or virus contamination)2
Treatment Technique Precursor Removal1
Failure to monitor or report, Routine/Repeat (Indicators of microbial or virus contamination)1