The Power of Information

National Drinking Water Database


607 systems serving 2,696,783 people

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

39 Contaminants Exceeding Health Based Limits

Contaminants detected in Connecticut 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)2,650,2342,650,234462462
Combined Radium (-226 & -228)1,175,2331,175,233330330
Combined Uranium (mg/L)972,301972,301415415
Alpha particle activity (excl radon and uranium)705,543705,543300300
Arsenic (total)650,241650,2412626
Total trihalomethanes (TTHMs)431,300431,30022
Total haloacetic acids (HAAs)431,300431,30022

Water Utilities in Connecticut Reporting Chemicals Exceeding Health Guidelines

Water utilities in Connecticut 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
Scwa Tower-Ferry View Division (Twr-Fvh)2,567681611
Meriden Water Division58,441681910
East Hampton Wpca - Village Center366681410
Hill Hollow Association48721810
Denlar Apartments - Buildings 17 & 1936431610
Valley Water Systems, Inc.17,07871179
Ledyard Wpca, Sablewoods System22068129
CTWC - Unionville Water Company13,06872189
United Water Ct, Inc. - Woodbury System1,64272158
Rsk Realty 13671128
South Norwalk Electric and Water42,00057128
Scwa, Gray Farms Division (Grf)46069148
East Lyme Water & Sewer Commission15,24582128
Durham Lexington Place Division4570158
Colchester Sewer & Water Commission4,00168128
High Meadow Condominiums23769138
Sandy Lane Village Condominium Assn31872128
Whisconier Village Association12369118
Rural Water Co, Inc-Brookfield Div.1,03269118
Hyde School - System #2 (Residential)31069107

Sources of Connecticut Drinking Water Contaminants

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

67Total Contaminants Detected (2004 - 2009)
22Agricultural Pollutants
(pesticides, fertilizer, factory farms)

Arsenic (total), Cyanide, Nitrate & nitrite, Nitrate, Nitrite, Selenium (total), Endrin, Lindane, Methoxychlor, Toxaphene, Dalapon, Oxamyl (Vydate), Atrazine, Alachlor (Lasso), 2,4-D, 2,4,5-TP (Silvex), 1,2-Dibromo-3-chloropropane (DBCP), Ethylene dibromide (EDB), o-Dichlorobenzene, p-Dichlorobenzene, 1,2-Dichloropropane, Ethylbenzene

20Sprawl 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), Lindane, Dalapon, Di(2-Ethylhexyl) adipate, 2,4-D, 2,4,5-TP (Silvex), Benzo[a]pyrene, Dichloromethane (methylene chloride), p-Dichlorobenzene, Tetrachloroethylene, Benzene

46Industrial Pollutants

Arsenic (total), Barium (total), Cadmium (total), Chromium (total), Cyanide, Lead (total), Mercury (total inorganic), Nitrate & nitrite, Nitrate, Nitrite, Selenium (total), Antimony (total), Beryllium (total), Thallium (total), Asbestos, Lindane, Di(2-Ethylhexyl) adipate, Di(2-ethylhexyl) phthalate, Hexachlorocyclopentadiene, Hexachlorobenzene (HCB), 1,2,4-Trichlorobenzene, cis-1,2-Dichloroethylene, Ethylene dibromide (EDB), 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, Alpha particle activity (excl radon and uranium), Combined Uranium (mg/L), Combined Radium (-226 & -228), Radium-226, Radium-228, Strontium-90, Combined Uranium (pCi/L), Gross beta particle activity (pCi/L)

13Water 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, Monochloroacetic acid, Di(2-ethylhexyl) phthalate, Cadmium (total), Vinyl chloride, Asbestos, Benzo[a]pyrene

18Naturally Occurring
(naturally present but increased for lands denuded by sprawl, agriculture, or industrial development)

Nitrate, Copper, Nitrate & nitrite, Barium (total), Lead (total), Arsenic (total), 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), Combined Uranium (mg/L), Selenium (total), Nitrite, Mercury (total inorganic), Cyanide

2Unregulated Contaminants
EPA has not established a maximum legal limit in tapwater for these contaminants

Lead (total), Strontium-90

Testing Summary for Connecticut

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

Contaminants reported as tested by water suppliers in Connecticut90
 Contaminants tested due to federal law: 88
 Contaminants tested in addition to those required by federal law: 2

Violation Summary for Connecticut

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

Violation TypeNumber of Violations
Failure to monitor regularly5,764
Failure to report information to the public or state agency in the Consumer Confidence Report595
Inadequate reporting of information to the public566
Failure to monitor, Routine Major (Coliform bacteria)370
Monitoring and Reporting Disinfection Byproduct Rule363
Over maximum contaminant level, Average337
Maximum contaminant level, Monthly (Coliform bacteria)310
Public Notification Violation for National Primary Drinking Water Regulations228
Failure to monitor, Routine Minor (Coliform bacteria)50
Failure to monitor or report, Routine/Repeat (Indicators of microbial or virus contamination)41
Other Non-National Primary Drinking Water Regulations Potential Health Risks41
Maximum contaminant level, Acute (Coliform bacteria)34
Follow-up and Routine Tap Sampling34
Failure to monitor, Repeat Major (Coliform bacteria)28
Initial Water Quality Parameter Monitoring and Reporting20
Public Education18
Optimal Corrosion Control Treatment Study Recommendation12
Initial, Follow-up, or Routine Source Water Treatment Monitoring and Reporting5
Initial Tap Sampling for Lead and Copper5
Over maximum contaminant level, Single Sample4
Treatment Technique Precursor Removal3
Failure to monitor, Repeat Minor (Coliform bacteria)3
Filter Turbidity Reporting3
Excess Turbidity at 0.3 NTU1