The Power of Information

National Drinking Water Database


1,135 systems serving 2,661,554 people

This drinking water quality report shows results of tests conducted by water utilities in Iowa, provided to the Environmental Working Group (EWG) by the Iowa Department of Natural Resources. 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.

38 Contaminants Exceeding Health Based Limits

Contaminants detected in Iowa 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
Lead (total)2,456,8562,456,856884884
Dichloroacetic acid2,289,5792,289,579650650
Total haloacetic acids (HAAs)2,106,5012,079,000455454
Total trihalomethanes (TTHMs)2,403,5771,906,200706489
Combined Radium (-226 & -228)835,303835,303324324

Water Utilities in Iowa Reporting Chemicals Exceeding Health Guidelines

Water utilities in Iowa 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
Sioux City Water Supply85,028612414
Sergeant Bluff Water Supply3,321621914
Storm Lake Water Treatment Plant10,329642314
Stacyville Water Supply469601913
Iowa Falls Water Department5,193621813
Lawton Water Supply697611712
Creston Water Supply7,597632312
Little Sioux Water Department222522012
Scranton Water System604601712
Nora Springs Water Supply1,532641812
Osceola Water Works4,659571712
Glidden Water Supply1,253822012
Salix Water Supply370611511
Kalona Water Dept2,293561811
Boyden Municipal Water Supply687481611
Odebolt Water Supply1,160511711
Montezuma Muni Water Supply1,457581711
Carson Water Supply668591611
West Des Moines Water Works54,293511911
City of Ankeny36,161611911

Sources of Iowa Drinking Water Contaminants

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

83Total Contaminants Detected (2004 - 2009)
23Agricultural Pollutants
(pesticides, fertilizer, factory farms)

Nitrate, Nitrate & nitrite, Arsenic (total), Selenium (total), Nitrite, Atrazine, Ethylbenzene, Dalapon, Simazine, Chlorate, 1,2-Dichloropropane, Dacthal, Metolachlor, p-Dichlorobenzene, Phosphorus, 2,4-D, Bromomethane, Alachlor (Lasso), Methoxychlor, Bromacil, Acetochlor, Cyanazine (Bladex), Desethylatrazine

28Sprawl and Urban Pollutants
(road runoff, lawn pesticides, human waste)

Nitrate, Copper, Nitrate & nitrite, Lead (total), Arsenic (total), Tetrachloroethylene, MTBE, Nitrite, Xylenes (total), Dalapon, Antimony (total), Mercury (total inorganic), Dichloromethane (methylene chloride), Benzene, Dacthal, p-Dichlorobenzene, Di(2-Ethylhexyl) adipate, Phosphorus, Di-n-butylphthalate, 2,4-D, Naphthalene, Benzo[a]pyrene, n-Propylbenzene, Phenanthrene, Pyrene, Fluoranthene, Fluorene, Acenaphthene

55Industrial Pollutants

Aluminum, Arsenic (total), Chlorate, Chlorite, Barium (total), Chromium (total), Lead (total), Manganese, Mercury (total inorganic), Nitrate & nitrite, Nitrate, Nitrite, Selenium (total), Antimony (total), Phosphorus, Di(2-Ethylhexyl) adipate, Di(2-ethylhexyl) phthalate, Chloromethane, Chloroethane, Naphthalene, MTBE, Acenaphthene, Fluorene, Phenanthrene, Fluoranthene, Pyrene, Di-n-butylphthalate, cis-1,2-Dichloroethylene, Dibromomethane, 1,2,4-Trimethylbenzene, 1,3,5-Trimethylbenzene, Bromochloromethane, Xylenes (total), Dichloromethane (methylene chloride), p-Dichlorobenzene, Vinyl chloride, 1,1-Dichloroethane, 1,2-Dichloroethane, 1,1,1-Trichloroethane, 1,2-Dichloropropane, Trichloroethylene, Tetrachloroethylene, Benzene, Toluene, Ethylbenzene, Styrene, n-Propylbenzene, Alpha particle activity (excl radon and uranium), Alpha particle activity (incl. radon & uranium), Combined Uranium (mg/L), Combined Radium (-226 & -228), Radium-226, Radium-228, Combined Uranium (pCi/L), Gross beta particle activity (pCi/L)

22Water 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, Chloromethane, Chlorate, Bromate, Vinyl chloride, Dibromomethane, Bromochloromethane, Benzo[a]pyrene, Chloroethane, Fluoranthene

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 (excl radon and uranium), Combined Radium (-226 & -228), Gross beta particle activity (pCi/L), Combined Uranium (pCi/L), Chromium (total), Alpha particle activity (incl. radon & uranium), Combined Uranium (mg/L), Aluminum, Selenium (total), Nitrite, Radon, Mercury (total inorganic), Chloromethane, Phosphorus

26Unregulated Contaminants
EPA has not established a maximum legal limit in tapwater for these contaminants

Chlorate, Lead (total), Phosphorus, Acetochlor, Metolachlor, Cyanazine (Bladex), Bromacil, Dacthal, Chloromethane, Bromomethane, Chloroethane, Naphthalene, MTBE, Acenaphthene, Fluorene, Phenanthrene, Fluoranthene, Pyrene, Di-n-butylphthalate, Dibromomethane, 1,2,4-Trimethylbenzene, 1,3,5-Trimethylbenzene, Bromochloromethane, 1,1-Dichloroethane, n-Propylbenzene, Radon

Testing Summary for Iowa

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

Contaminants reported as tested by water suppliers in Iowa166
 Contaminants tested due to federal law: 96
 Contaminants tested in addition to those required by federal law: 70

Violation Summary for Iowa

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

Violation TypeNumber of Violations
Failure to monitor, Routine Major (Coliform bacteria)305
Maximum contaminant level, Monthly (Coliform bacteria)297
Over maximum contaminant level, Average276
Failure to monitor regularly275
Monitoring and Reporting Disinfection Byproduct Rule250
Failure to report information to the public or state agency in the Consumer Confidence Report127
Record Keeping Violation106
Over maximum contaminant level, Single Sample82
Failure to monitor, Routine Minor (Coliform bacteria)77
Follow-up and Routine Tap Sampling58
Maximum contaminant level, Acute (Coliform bacteria)24
Failure to monitor, Repeat Major (Coliform bacteria)20
Excess Turbidity at 0.3 NTU12
Operations Report6
Excess Turbidity at 1 NTU6
Filter Turbidity Reporting5
Failure to monitor: Check/Repeat/Confirmation sampling5
Inadequate reporting of information to the public4
Variance/Exemption/Other Compliance3
Treatment Technique (Surface Water Treatment Rule)3
Improper Treatment Techniques2
Failure to monitor, Repeat Minor (Coliform bacteria)2
Failure to notify state agency1
Public Education1
Optimal Corrosion Control Treatment Study Recommendation1
Failure to notify public of violation1