1,765 systems serving 13,084,369 people
  This drinking water quality report shows results of tests conducted by water utilities in Illinois, provided to the Environmental Working Group (EWG) by the Illinois Environmental Protection Agency. 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.

  63 Contaminants Exceeding Health Based Limits

Contaminants detected in Illinois 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) 12,319,906 12,319,906 1,345 1,345
Bromodichloromethane 12,229,020 12,229,020 1,195 1,195
Dibromochloromethane 11,896,659 11,883,519 1,114 1,112
Total trihalomethanes (TTHMs) 12,650,186 11,847,956 1,476 1,031
Dichloroacetic acid 11,715,567 11,715,567 1,169 1,169
Chloroform 12,493,882 11,399,380 1,391 872
Lead (total) 11,228,655 11,228,655 1,196 1,196
Radium-226 8,033,465 8,033,465 894 894
Radium-228 7,960,993 7,960,993 871 871
Combined Radium (-226 & -228) 7,893,389 7,893,389 918 918

  Sources of Illinois Drinking Water Contaminants

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

101 Total Contaminants Detected (2004 - 2009)
31 Agricultural Pollutants
(pesticides, fertilizer, factory farms)

Nitrate, Nitrate & nitrite, Arsenic (total), Selenium (total), Nitrite, 1,2-Dibromo-3-chloropropane (DBCP), Atrazine, Ethylbenzene, Dalapon, Cyanide, n-Nitrosodimethylamine, Simazine, Ethylene dibromide (EDB), 1,2-Dichloropropane, Metolachlor, p-Dichlorobenzene, Phosphorus, 2,4-D, Heptachlor epoxide, Monochlorobenzene (Chlorobenzene), Alachlor (Lasso), Lindane, Picloram, Dicamba, Diquat, Methoxychlor, Endrin, Heptachlor, Aldicarb sulfone, Acetochlor, Trifluralin

30 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), Dichloromethane (methylene chloride), Cyanide, Benzene, Molybdenum, Silver (total), p-Dichlorobenzene, Methyl ethyl ketone, Di(2-Ethylhexyl) adipate, Phosphorus, 2,4-D, Benzo[a]pyrene, Lindane, Indeno[1,2,3-cd]pyrene, Benzo[b]fluoranthene, Phenols, Benzo[k]fluoranthene, Trifluralin

68 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), Combined Uranium (pCi/L), Tetrachloroethylene, Trichloroethylene, Chromium (total), Combined Uranium (mg/L), Aluminum, Selenium (total), MTBE, Nitrite, Xylenes (total), cis-1,2-Dichloroethylene, Chlorite, 1,1-Dichloroethylene, Vanadium, Di(2-ethylhexyl) phthalate, Bromide, Carbon tetrachloride, Ethylbenzene, Toluene, 1,1,1-Trichloroethane, Cadmium (total), Antimony (total), Mercury (total inorganic), Chloromethane, Dichloromethane (methylene chloride), Cyanide, Beryllium (total), Thallium (total), 1,2-Dichloroethane, n-Nitrosodimethylamine, Benzene, Molybdenum, Ethylene dibromide (EDB), 1,2-Dichloropropane, Silver (total), Tritium, Strontium, Vinyl chloride, p-Dichlorobenzene, Methyl ethyl ketone, Di(2-Ethylhexyl) adipate, trans-1,2-Dichloroethylene, Asbestos, Phosphorus, Hexachlorocyclopentadiene, Tetrahydrofuran, Styrene, Monochlorobenzene (Chlorobenzene), Pentachlorophenol, Bromochloromethane, Lindane, 1,2,4-Trichlorobenzene, Indeno[1,2,3-cd]pyrene, Benzo[b]fluoranthene, Phenols, N-nitrosopyrrolidine (npyr)

22 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, Monobromoacetic acid, Chlorite, Di(2-ethylhexyl) phthalate, Cadmium (total), Chloromethane, n-Nitrosodimethylamine, Bromate, Vinyl chloride, Asbestos, Bromochloromethane, Benzo[a]pyrene, Benzo[k]fluoranthene

25 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), Combined Uranium (pCi/L), Chromium (total), Combined Uranium (mg/L), Aluminum, Selenium (total), Nitrite, Bromide, Mercury (total inorganic), Chloromethane, Cyanide, Silver (total), Phosphorus

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

Bromide, Lead (total), Strontium, Molybdenum, Vanadium, Phosphorus, Acetochlor, Aldicarb sulfone, Metolachlor, Trifluralin, Chloromethane, Methyl ethyl ketone, MTBE, Tetrahydrofuran, Benzo[b]fluoranthene, Benzo[k]fluoranthene, Indeno[1,2,3-cd]pyrene, n-Nitrosodimethylamine, Bromochloromethane, Dicamba, Phenols, Tritium, N-nitrosopyrrolidine (npyr), Uranium-234 (pCi/L)

  Testing Summary for Illinois

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

Contaminants reported as tested by water suppliers in Illinois 226
  Contaminants tested due to federal law: 95
  Contaminants tested in addition to those required by federal law: 131
  Violation Summary for Illinois

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

Violation Type Number of Violations
Failure to monitor regularly 2,157
Over maximum contaminant level, Average 1,891
Monitoring and Reporting Disinfection Byproduct Rule 741
Public Notification Violation for National Primary Drinking Water Regulations 505
Failure to monitor, Routine Major (Coliform bacteria) 439
Other Non-National Primary Drinking Water Regulations Potential Health Risks 416
Inadequate reporting of information to the public 290
Treatment Technique (Surface Water Treatment Rule) 232
Maximum contaminant level, Monthly (Coliform bacteria) 207
Failure to report information to the public or state agency in the Consumer Confidence Report 205
Failure to monitor, Routine Minor (Coliform bacteria) 178
Initial Water Quality Parameter Monitoring and Reporting 128
Failure to monitor, Repeat Major (Coliform bacteria) 110
Follow-up and Routine Tap Sampling 79
Failure to monitor, Repeat Minor (Coliform bacteria) 49
Excess Turbidity at 0.3 NTU 49
Treatment Technique Precursor Removal 41
Public Education 22
Excess Turbidity at 1 NTU 20
Initial Tap Sampling for Lead and Copper 18
Maximum contaminant level, Acute (Coliform bacteria) 15
Optimal Corrosion Control Treatment Study Recommendation 15
Water Quality Program Entry Point Non-Compliance 10
Filter Turbidity Reporting 7
Failure to monitor or report, Routine/Repeat (Indicators of microbial or virus contamination) 5
Non-Acute maximum residual disinfectant level 3
Optimal Corrosion Control Treatment Installation/Demonstration 3
Over maximum contaminant level, Single Sample 2
Initial, Follow-up, or Routine Source Water Treatment Monitoring and Reporting 2
Treatment Technique w/o State Prior Approval 2

Sources : EWG (Environmental Working Group)