The Power of Information

National Drinking Water Database


212 systems serving 889,111 people

This drinking water quality report shows results of tests conducted by water utilities in Delaware, provided to the Environmental Working Group (EWG) by the Delaware Health and Social Services- Division of Public Health. 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.

74 Contaminants Exceeding Health Based Limits

Contaminants detected in Delaware 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
Alpha particle activity879,416879,416200200
Total haloacetic acids (HAAs)846,593846,593115115
Lead (total)788,753788,753139139
Dichloroacetic acid761,580761,580100100
Total trihalomethanes (TTHMs)875,080729,10014675
Arsenic (total)664,621664,6216565

Water Utilities in Delaware Reporting Chemicals Exceeding Health Guidelines

Water utilities in Delaware 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
Artesian Water Company201,00020313854
Millsboro Water Department2,3001855018
South Bethany12,0001893016
Newark Water Department36,1301963615
Cedar Landing3201893314
Townsend Water Department1,5001913014
Thomas Cove3,4001844313
Sea Winds1051932213
Fox Hunter Crossing1,4701883413
Frankford Water Department9001642313
Paradise Estates2251952212
Deer Meadows2851862112
Church Creek2,7001913212
Beaver Creek3501832711
Sandy Ridge Mobile Home Park1801961911
Laurel District751952211
Augustine Creek4251893211
Wild Quail District7921882711

Sources of Delaware Drinking Water Contaminants

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

170Total Contaminants Detected (2004 - 2007)
55Agricultural Pollutants
(pesticides, fertilizer, factory farms)

Nitrate, Nitrate & nitrite, Arsenic (total), Selenium (total), Nitrite, 1,2-Dibromo-3-chloropropane (DBCP), Atrazine, Ethylbenzene, Dalapon, Cyanide, Simazine, Ethylene dibromide (EDB), Dacthal, Metolachlor, p-Dichlorobenzene, 2,4-D, Heptachlor epoxide, Monochlorobenzene (Chlorobenzene), Chlordane, Alachlor (Lasso), Lindane, Picloram, Dieldrin, Dinoseb, Dicamba, Toxaphene, Oxamyl (Vydate), 2,4,5-TP (Silvex), Methoxychlor, 3-Hydroxycarbofuran, Endrin, Aldicarb sulfoxide, Heptachlor, Carbofuran, Methomyl, Aldicarb, Carbaryl, Metribuzin, Aldicarb sulfone, Aldrin, Propachlor, Di-n-octylphthalate, Iodomethane, Alpha Chlordane, para-para DDE, Gamma Chlordane, p,p'-DDT, para-para DDD, delta-BHC, Endrin Aldehyde, alpha-Lindane, beta-Lindane, Endosulfan I, Endosulfan II, Endosulfan Sulfate

57Sprawl and Urban Pollutants
(road runoff, lawn pesticides, human waste)

Nitrate, Copper, Nitrate & nitrite, Lead (total), Arsenic (total), Tetrachloroethylene, MTBE, Nitrite, Xylenes (total), Dalapon, Cadmium (total), Antimony (total), Mercury (total inorganic), m- & p- Xylene, Dichloromethane (methylene chloride), Cyanide, o-Xylene, Benzene, Acetone, Molybdenum, Silver (total), Trichlorofluoromethane, Dacthal, p-Dichlorobenzene, Methyl ethyl ketone, Di(2-Ethylhexyl) adipate, Di-n-butylphthalate, 2,4-D, Naphthalene, Chlordane, Benzo[a]pyrene, Lindane, Diethylphthalate, bis(2-ethylhexyl) phthalate, n-Propylbenzene, 2,4,5-TP (Silvex), Phenanthrene, Pyrene, Carbaryl, Butyl Benzylphthalate, Fluoranthene, Fluorene, sec-Butylbenzene, Indeno[1,2,3-cd]pyrene, Chrysene, Benzo[b]fluoranthene, Benzo[g,h,i]perylene, Anthracene, Benzo[k]fluoranthene, Benzo[a]anthracene, Acenaphthene, Dimethylphthalate, Dibenz[a,h]anthracene, Di-n-octylphthalate, 2-Methyl naphthalene, alpha-Lindane, beta-Lindane

114Industrial Pollutants

Nitrate, Nitrate & nitrite, Barium (total), Lead (total), Arsenic (total), Manganese, Radium-228, Radium-226, Alpha particle activity, Alpha particle activity (excl radon and uranium), Combined Radium (-226 & -228), Gross beta particle activity (pCi/L), Tetrachloroethylene, Trichloroethylene, Chromium (total), Aluminum, Selenium (total), MTBE, Nitrite, Xylenes (total), cis-1,2-Dichloroethylene, 1,1-Dichloroethylene, Di(2-ethylhexyl) phthalate, 1,2,3-Trichloropropane, Carbon tetrachloride, Ethylbenzene, Toluene, 1,1,1-Trichloroethane, Cadmium (total), Dichlorodifluoromethane, Antimony (total), Mercury (total inorganic), 1,1-Dichloroethane, m- & p- Xylene, Chloromethane, Dichloromethane (methylene chloride), Cyanide, o-Xylene, Beryllium (total), Thallium (total), 1,2-Dichloroethane, Benzene, Acetone, Molybdenum, Ethylene dibromide (EDB), Silver (total), Tritium, Trichlorofluoromethane, Vinyl chloride, p-Dichlorobenzene, Methyl ethyl ketone, Di(2-Ethylhexyl) adipate, Strontium-90, Asbestos, Hexachlorocyclopentadiene, Tetrahydrofuran, Styrene, Di-n-butylphthalate, Naphthalene, Monochlorobenzene (Chlorobenzene), 1,2,4-Trimethylbenzene, Methyl isobutyl ketone, Pentachlorophenol, Dibromomethane, Bromochloromethane, 1,1,2-Trichloroethane, Chloroethane, Lindane, Diethylphthalate, 1,2,4-Trichlorobenzene, bis(2-ethylhexyl) phthalate, 1,3,5-Trimethylbenzene, Gross beta particle activity (mrem/yr), n-Propylbenzene, Phenanthrene, 1,2,3-Trichlorobenzene, Hexachlorobenzene (HCB), Pyrene, bis(2-chloroethyl) ether, o-Chlorotoluene, 1,1,1,2-Tetrachloroethane, Butyl Benzylphthalate, Fluoranthene, Fluorene, Hexachlorobutadiene, sec-Butylbenzene, 2,2-Dichloropropane, Indeno[1,2,3-cd]pyrene, 1,1,2,2-Tetrachloroethane, p-Chlorotoluene, Chrysene, Benzo[b]fluoranthene, cis-1,3-Dichloropropene, 1,3-Dichloropropane, Anthracene, Acenaphthylene, Acenaphthene, Aroclor 1242, Aroclor 1254, Aroclor 1221, Dimethylphthalate, Dibenz[a,h]anthracene, Aroclor 1260, Aroclor 1232, Aroclor 1248, Aroclor 1016, Di-n-octylphthalate, Acrylonitrile, Iodomethane, 2-Methyl naphthalene, Dibenzofuran, Endosulfan I, Endosulfan II, Endosulfan Sulfate

25Water 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, Vinyl chloride, Asbestos, Dibromomethane, Bromochloromethane, Benzo[a]pyrene, Chloroethane, Fluoranthene, Benzo[g,h,i]perylene, Benzo[k]fluoranthene, Benzo[a]anthracene

23Naturally Occurring
(naturally present but increased for lands denuded by sprawl, agriculture, or industrial development)

Nitrate, Copper, Nitrate & nitrite, Barium (total), Lead (total), Arsenic (total), Manganese, Radium-228, Radium-226, Alpha particle activity, Alpha particle activity (excl radon and uranium), Combined Radium (-226 & -228), Gross beta particle activity (pCi/L), Chromium (total), Aluminum, Selenium (total), Nitrite, Mercury (total inorganic), Chloromethane, Cyanide, Silver (total), Gross beta particle activity (mrem/yr), 2-Methyl naphthalene

82Unregulated Contaminants
EPA has not established a maximum legal limit in tapwater for these contaminants

Lead (total), Molybdenum, Carbaryl, Methomyl, Aldicarb sulfoxide, Aldicarb sulfone, Metolachlor, Aldicarb, 3-Hydroxycarbofuran, Endosulfan I, para-para DDE, Dieldrin, para-para DDD, Endosulfan II, Endosulfan Sulfate, p,p'-DDT, Propachlor, Dacthal, Dibenzofuran, Chloromethane, Dichlorodifluoromethane, Chloroethane, Trichlorofluoromethane, bis(2-chloroethyl) ether, Di-n-octylphthalate, cis-1,3-Dichloropropene, Acrylonitrile, 2-Methyl naphthalene, Acetone, Hexachlorobutadiene, Methyl ethyl ketone, Naphthalene, Methyl isobutyl ketone, MTBE, Acenaphthylene, Acenaphthene, Tetrahydrofuran, Fluorene, Phenanthrene, Anthracene, Dimethylphthalate, Diethylphthalate, Fluoranthene, Pyrene, Di-n-butylphthalate, Butyl Benzylphthalate, Chrysene, bis(2-ethylhexyl) phthalate, Benzo[a]anthracene, Benzo[b]fluoranthene, Benzo[k]fluoranthene, Indeno[1,2,3-cd]pyrene, Dibenz[a,h]anthracene, Benzo[g,h,i]perylene, alpha-Lindane, beta-Lindane, delta-BHC, Aldrin, Endrin Aldehyde, Dibromomethane, 1,3-Dichloropropane, 1,2,3-Trichloropropane, 2,2-Dichloropropane, 1,2,4-Trimethylbenzene, 1,2,3-Trichlorobenzene, 1,3,5-Trimethylbenzene, sec-Butylbenzene, Bromochloromethane, Dicamba, Bromochloroacetic acid, Iodomethane, Metribuzin, o-Chlorotoluene, p-Chlorotoluene, 1,1-Dichloroethane, 1,1,1,2-Tetrachloroethane, 1,1,2,2-Tetrachloroethane, n-Propylbenzene, Tritium, Strontium-90, Alpha Chlordane, Gamma Chlordane

Testing Summary for Delaware

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

Contaminants reported as tested by water suppliers in Delaware233
 Contaminants tested due to federal law: 96
 Contaminants tested in addition to those required by federal law: 137

Violation Summary for Delaware

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

Violation TypeNumber of Violations
Maximum contaminant level, Monthly (Coliform bacteria)66
Failure to report information to the public or state agency in the Consumer Confidence Report52
Over maximum contaminant level, Average42
Initial Water Quality Parameter Monitoring and Reporting39
Initial Tap Sampling for Lead and Copper22
Follow-up and Routine Tap Sampling12
Maximum contaminant level, Acute (Coliform bacteria)9
Inadequate reporting of information to the public7
Failure to monitor, Repeat Minor (Coliform bacteria)2
Failure to monitor, Routine Minor (Coliform bacteria)2
Failure to monitor regularly2
Improper Treatment Techniques1
Treatment Technique No Certif. Operator1
Initial, Follow-up, or Routine Source Water Treatment Monitoring and Reporting1
Failure to monitor, Routine Major (Coliform bacteria)1
Treatment Technique (Surface Water Treatment Rule)1
Public Notification Violation for National Primary Drinking Water Regulations1