The Power of Information

National Drinking Water Database


1,297 systems serving 10,103,190 people

This drinking water quality report shows results of tests conducted by water utilities in Ohio, provided to the Environmental Working Group (EWG) by the Ohio Environmental Protection Agency- Division of Drinking and Ground Waters. 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.

45 Contaminants Exceeding Health Based Limits

Contaminants detected in Ohio 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)9,972,7739,972,1731,0841,083
Total trihalomethanes (TTHMs)10,025,0089,767,6721,143829
Dichloroacetic acid9,307,6909,307,690686686
Arsenic (total)2,698,9212,698,921287287

Water Utilities in Ohio Reporting Chemicals Exceeding Health Guidelines

Water utilities in Ohio 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
Ohio-American Water Co-Beechcrest Pws1,375612314
Village of Lakemore2,865921913
City of Cortland6,830901912
City of Sidney20,2111282012
Ohio American Water Co-Tiffin District18,135942412
Village of New Holland870531812
Wright-Patterson Afb Area A/C Pws11,7911161812
Cleveland Division of Water1,500,000582712
Maplewood Park450521611
Village of Gibsonburg2,600491711
Lakengren Water Authorit2,400861711
Oh/Am Water Company-Mari48,000972411
Village of Mcclure850701611
Washington Court House Pws13,892692011
City of Urbana11,3531051611
Minster Water Treatment Plant2,650881511
City of Upper Sandusky6,600842010
City of Wooster26,000492010
Village of Shiloh792521810
Ottawa Water Treatment Plant4,196961910

Sources of Ohio Drinking Water Contaminants

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

80Total Contaminants Detected (2004 - 2009)
19Agricultural Pollutants
(pesticides, fertilizer, factory farms)

Arsenic (total), Cyanide, Nitrate & nitrite, Nitrate, Nitrite, Selenium (total), Phosphorus, Diquat, Simazine, Picloram, Metolachlor, Atrazine, Alachlor (Lasso), 2,4-D, Bromomethane, Metribuzin, p-Dichlorobenzene, 1,2-Dichloropropane, Ethylbenzene

24Sprawl and Urban Pollutants
(road runoff, lawn pesticides, human waste)

Arsenic (total), Cadmium (total), Copper, Cyanide, Lead (total), Mercury (total inorganic), Nitrate & nitrite, Nitrate, Nitrite, Antimony (total), Molybdenum, Phosphorus, 2,4-D, Acetone, MTBE, Benzo[a]pyrene, sec-Butylbenzene, Xylenes (total), p-Xylene, Dichloromethane (methylene chloride), p-Dichlorobenzene, Tetrachloroethylene, Benzene, o-Xylene

58Industrial Pollutants

Aluminum, Arsenic (total), Chlorite, Barium (total), Cadmium (total), Chromium (total), Cyanide, Lead (total), Manganese, Mercury (total inorganic), Nitrate & nitrite, Nitrate, Nitrite, Selenium (total), Strontium, Antimony (total), Beryllium (total), Chromium (hexavalent), Molybdenum, Thallium (total), Phosphorus, Asbestos, Di(2-ethylhexyl) phthalate, Chloromethane, Acetone, MTBE, Pentachlorophenol, 1,2,4-Trichlorobenzene, cis-1,2-Dichloroethylene, Total polychlorinated biphenyls (PCBs), 1,2,3-Trichlorobenzene, sec-Butylbenzene, Bromochloromethane, Xylenes (total), p-Xylene, Dichloromethane (methylene chloride), p-Dichlorobenzene, Vinyl chloride, 1,1-Dichloroethylene, trans-1,2-Dichloroethylene, 1,2-Dichloroethane, 1,1,1-Trichloroethane, Carbon tetrachloride, 1,2-Dichloropropane, Trichloroethylene, 1,1,2-Trichloroethane, Tetrachloroethylene, Benzene, Toluene, Ethylbenzene, Styrene, o-Xylene, Alpha particle activity (excl radon and uranium), Alpha particle activity (incl. radon & uranium), Combined Radium (-226 & -228), Radium-226, Radium-228, Gross beta particle activity (pCi/L)

19Water 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, Vinyl chloride, Asbestos, Bromochloromethane, Benzo[a]pyrene

22Naturally 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), Chromium (total), Alpha particle activity (incl. radon & uranium), Aluminum, Selenium (total), Nitrite, Chromium (hexavalent), Mercury (total inorganic), Chloromethane, Cyanide, Phosphorus

13Unregulated Contaminants
EPA has not established a maximum legal limit in tapwater for these contaminants

Lead (total), Strontium, Molybdenum, Phosphorus, Metolachlor, Chloromethane, Bromomethane, Acetone, MTBE, 1,2,3-Trichlorobenzene, sec-Butylbenzene, Bromochloromethane, Metribuzin

Testing Summary for Ohio

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

Contaminants reported as tested by water suppliers in Ohio155
 Contaminants tested due to federal law: 98
 Contaminants tested in addition to those required by federal law: 57

Violation Summary for Ohio

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

Violation TypeNumber of Violations
Failure to monitor regularly2,497
Over maximum contaminant level, Average664
Failure to monitor, Routine Major (Coliform bacteria)524
Monitoring and Reporting Disinfection Byproduct Rule364
Inadequate reporting of information to the public217
Failure to report information to the public or state agency in the Consumer Confidence Report182
Follow-up and Routine Tap Sampling143
Treatment Technique (Surface Water Treatment Rule)137
Maximum contaminant level, Monthly (Coliform bacteria)125
Failure to monitor, Routine Minor (Coliform bacteria)107
Maximum contaminant level, Acute (Coliform bacteria)41
Filter Turbidity Reporting37
Failure to monitor, Repeat Major (Coliform bacteria)37
Excess Turbidity at 0.3 NTU32
Failure to monitor or report, Routine/Repeat (Indicators of microbial or virus contamination)28
Treatment Technique Precursor Removal22
Excess Turbidity at 1 NTU20
Public Education10
Initial Tap Sampling for Lead and Copper8
Failure to monitor, Repeat Minor (Coliform bacteria)7
Initial Water Quality Parameter Monitoring and Reporting6
Optimal Corrosion Control Treatment Study Recommendation4
Failure to Filter (Surface Water Treatment Rule)3
Over maximum contaminant level, Single Sample2
Water Quality Program Entry Point Non-Compliance1
Public Notification Violation for National Primary Drinking Water Regulations1
Optimal Corrosion Control Treatment Installation/Demonstration1