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 Limitss

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 activity 879,416 879,416 200 200
Bromodichloromethane 858,737 858,737 122 122
Dibromochloromethane 857,987 855,537 111 109
Total haloacetic acids (HAAs) 846,593 846,593 115 115
Lead (total) 788,753 788,753 139 139
Dichloroacetic acid 761,580 761,580 100 100
Total trihalomethanes (TTHMs) 875,080 729,100 146 75
Bromoform 683,433 683,433 70 70
Chloroform 834,852 669,248 139 63
Arsenic (total) 664,621 664,621 65 65

  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.

170 Total Contaminants Detected (2004 - 2007)
55 Agricultural 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

57 Sprawl 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

114 Industrial 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

25 Water 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

23 Naturally 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

82 Unregulated 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 Delaware 233
  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 Type Number of Violations
Maximum contaminant level, Monthly (Coliform bacteria) 66
Failure to report information to the public or state agency in the Consumer Confidence Report 52
Over maximum contaminant level, Average 42
Initial Water Quality Parameter Monitoring and Reporting 39
Initial Tap Sampling for Lead and Copper 22
Follow-up and Routine Tap Sampling 12
Maximum contaminant level, Acute (Coliform bacteria) 9
Inadequate reporting of information to the public 7
Failure to monitor, Routine Minor (Coliform bacteria) 2
Failure to monitor regularly 2
Failure to monitor, Repeat Minor (Coliform bacteria) 2
Improper Treatment Techniques 1
Treatment Technique No Certif. Operator 1
Initial, Follow-up, or Routine Source Water Treatment Monitoring and Reporting 1
Failure to monitor, Routine Major (Coliform bacteria) 1
Treatment Technique (Surface Water Treatment Rule) 1
Public Notification Violation for National Primary Drinking Water Regulations 1

Sources : EWG (Environmental Working Group)