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EWG's Tap Water Database — 2021 UPDATE

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Chlorate

Status: No national drinking water standard exists

 

Chlorate forms in drinking water as a byproduct of disinfection. Chlorate impairs thyroid function, making chlorate exposure most harmful during pregnancy and childhood. Read More.

In 2002, California scientists proposed an advisory value, called an action level, for chlorate at 200 parts per billion. Between 2013 and 2015, the EPA collected data through the Unregulated Contaminant Monitoring Rule program and found that over 15 percent of water tests from 38 percent of utilities had chlorate levels above a health-protective concentration, which federal scientists defined as 210 parts per billion, nearly equivalent to the California advisory value.

Click here to read more about disinfection byproducts.

2013-2019:

FOUND
FOUND ABOVE HEALTH GUIDELINES

50

states detected

5,931

utilities detected

208 million

people served

45

states over health guideline

1,562

utilities over health guideline

44 million

people served over health guideline

Health concerns for chlorate

Hormone disruption

State and national drinking water standards and health guidelines

EWG Health Guideline 210 ppb

The EWG Health Guideline of 210 ppb for chlorate was defined by the Environmental Protection Agency as a benchmark for testing under the Unregulated Contaminant Monitoring Rule program. This health guideline protects against hormone disruption.

ppb = parts per billion

States reporting chlorate in drinking water

UTILITIES REPORTING ABOVE HEALTH GUIDELINES UTILITIES WITH CONTAMINATION
State UtilitiesPeople Served UtilitiesPeople Served
California874,392,49552936,282,036
New York25625,96425317,690,129
Texas2084,063,57257217,338,633
Florida22410,708,06431416,644,694
New Jersey27711,3662188,146,676
Pennsylvania151,755,3192357,906,893
Ohio43823,6581816,569,681
Georgia321,733,1781316,359,067
North Carolina1122,235,6343426,209,266
Virginia863,405,0871356,046,387
Arizona8158,564865,437,678
Massachusetts34938,0331795,301,451
Maryland12245,001534,891,260
Washington5106,7021564,578,677
Tennessee40948,3031434,389,393
Alabama861,345,2781784,139,522
Illinois63463,6502323,714,078
Colorado18632,8071353,443,986
Kentucky51867,1661743,223,024
South Carolina721,120,4701613,032,839
Nevada00182,622,646
Connecticut12111,980702,466,470
Wisconsin899,356802,306,500
Oregon17719,696712,274,483
Indiana281,228,023592,264,213
Missouri35332,421672,126,386
Louisiana27926,543842,113,309
Michigan11169,8111051,900,175
Utah00531,845,238
Oklahoma42443,3081211,608,098
Arkansas22411,3291011,448,269
Kansas18169,706751,443,123
Iowa17174,9951451,301,243
New Mexico444,226291,269,376
Minnesota796,063331,230,574
Hawaii11,360161,206,829
Nebraska00281,061,900
Idaho0018716,766
Delaware5155,86114684,962
District Of Columbia3664,5723664,572
West Virginia234,31175641,104
Rhode Island350,18924591,905
New Hampshire8152,66043588,479
Mississippi352,55919480,104
Alaska8135,72420435,439
Maine446,87319420,453
South Dakota0052370,689
Wyoming1161,87235234,707
Montana120,0089187,743
Vermont1697,38634151,073
North Dakota179241,336
MORE
LESS

Utilities with the highest amounts of chlorate, 2013-2019

ALL UTILITIES
LARGE UTILITIES
UtilityLocationTestsAverage levelPeople served
Vc/halifax Plantation (wtp-8)Ormond Beach, FL4 of 42,530.0 ppb4,650
City of BonhamBonham, TX8 of 82,031.9 ppb10,123
Oak Shores Water SystemMontague, TX3 of 41,867.5 ppb210
VC/Southwest Water SystemOrange City, FL12 of 121,735.0 ppb17,563
SavageSavage, MN3 of 61,687.7 ppb30,285
AtkinsonPeru, IL4 of 41,432.9 ppb945
Willingboro MUA*Riverside, NJ8 of 81,379.0 ppb35,000
Pennsville Twsp. Water Depart.Pennsville, NJ7 of 81,316.4 ppb13,500
Middleton Water DepartmentMiddleton, MA11 of 111,244.5 ppb6,920
Danvers Water Department*Middleton, MA11 of 111,244.5 ppb26,493
Garden City PWSGarden City, MO7 of 71,211.4 ppb1,642
Texoma HillsMadill, OK8 of 101,161.6 ppb212
Marshall County Water Corp*Madill, OK8 of 101,161.6 ppb14,717
Houma Water Treatment Service AreaHouma, LA8 of 81,103.8 ppb31,560
Westwood BeachPflugerville, TX6 of 61,096.5 ppb1,770
Seminole County NortheastLake Mary, FL8 of 81,052.7 ppb19,925
St. MarysSt. Marys, GA5 of 61,047.7 ppb17,270
City of Terrell*Terrell, TX8 of 81,040.9 ppb17,500
Lawrence Water Supply CorporationTerrell, TX8 of 81,040.9 ppb1,095
Poetry Water Supply CorporationTerrell, TX8 of 81,040.9 ppb3,276
Elmo Water Supply CorporationElmo, TX8 of 81,040.9 ppb2,280
Alco Water ServiceSalinas, CA6 of 71,021.7 ppb29,179
Westside Rural Water Supply CorporationPflugerville, TX10 of 121,009.2 ppb975
Seymour Johnson Air Force BaseSeymour Johnson, NC8 of 81,007.0 ppb6,875
City of Goldsboro*Goldsboro, NC8 of 81,007.0 ppb34,959
City of WylieWylie, TX8 of 81,006.9 ppb44,418
Kaufman County Fresh Water Supply District 1aDallas, TX8 of 8989.6 ppb6,024
Talty Special Utility DistrictForney, TX8 of 8989.6 ppb9,570
Markout Water Supply CorporationForney, TX8 of 8989.6 ppb2,835
City of Forney*Forney, TX8 of 8989.6 ppb19,122
Okeechobee Utility AuthorityOkeechobee, FL12 of 12986.6 ppb20,000
Poplar BluffPoplar Bluff, MO8 of 8971.9 ppb17,266
Des Plaines Mobile Home ParkDesplaines, IL4 of 4968.5 ppb580
CentralWinter Haven, FL17 of 17968.2 ppb13,595
University of Central FloridaOrlando, FL4 of 4946.5 ppb44,108
Scranton Water SystemScranton, IA2 of 2939.5 ppb557
Broward County Water and Wastewater Services (BCWWS) - 1ALauderdale Lakes, FL4 of 4935.0 ppb75,305
Saint Basils AcademyGarrison, NY4 of 4921.3 ppb130
Longacre Estates Mobile Home ParkElkhart, IL8 of 8914.6 ppb375
Eastern Illinois UniversityCharleston, IL8 of 8914.6 ppb5,500
Charleston*Charleston, IL8 of 8914.6 ppb16,400
Town of Little Elm*Little Elm, TX6 of 6897.7 ppb41,796
Windermere CommunityPflugerville, TX24 of 24896.1 ppb20,091
New Mexico State UniversityLas Cruces, NM10 of 10865.4 ppb24,302
Southwest/Polk County UtilityLakeland, FL20 of 20863.7 ppb39,209
Blackland Water Supply CorporationFate, TX8 of 8849.0 ppb4,908
HannibalHannibal, MO6 of 6845.5 ppb17,916
Afton Public Works AuthorityAfton, OK8 of 8837.8 ppb1,428
Kaufman County Municipal Utility District 12*Dallas, TX8 of 8827.5 ppb0
City of Mesquite*Mesquite, TX8 of 8827.5 ppb143,350

* This water utility supplies finished drinking water to at least one other water utility. The purchasing utility is not required to test for or report Chlorate, but it likely has the contaminant in its water supply.

UtilityLocationTestsAverage levelPeople served
City of BonhamBonham, TX8 of 82,031.9 ppb10,123
VC/Southwest Water SystemOrange City, FL12 of 121,735.0 ppb17,563
SavageSavage, MN3 of 61,687.7 ppb30,285
Willingboro MUA*Riverside, NJ8 of 81,379.0 ppb35,000
Pennsville Twsp. Water Depart.Pennsville, NJ7 of 81,316.4 ppb13,500
Danvers Water Department*Middleton, MA11 of 111,244.5 ppb26,493
Marshall County Water Corp*Madill, OK8 of 101,161.6 ppb14,717
Houma Water Treatment Service AreaHouma, LA8 of 81,103.8 ppb31,560
Seminole County NortheastLake Mary, FL8 of 81,052.7 ppb19,925
St. MarysSt. Marys, GA5 of 61,047.7 ppb17,270
City of Terrell*Terrell, TX8 of 81,040.9 ppb17,500
Alco Water ServiceSalinas, CA6 of 71,021.7 ppb29,179
City of Goldsboro*Goldsboro, NC8 of 81,007.0 ppb34,959
City of WylieWylie, TX8 of 81,006.9 ppb44,418
City of Forney*Forney, TX8 of 8989.6 ppb19,122
Okeechobee Utility AuthorityOkeechobee, FL12 of 12986.6 ppb20,000
Poplar BluffPoplar Bluff, MO8 of 8971.9 ppb17,266
CentralWinter Haven, FL17 of 17968.2 ppb13,595
University of Central FloridaOrlando, FL4 of 4946.5 ppb44,108
Broward County Water and Wastewater Services (BCWWS) - 1ALauderdale Lakes, FL4 of 4935.0 ppb75,305
Charleston*Charleston, IL8 of 8914.6 ppb16,400
Town of Little Elm*Little Elm, TX6 of 6897.7 ppb41,796
Windermere CommunityPflugerville, TX24 of 24896.1 ppb20,091
New Mexico State UniversityLas Cruces, NM10 of 10865.4 ppb24,302
Southwest/Polk County UtilityLakeland, FL20 of 20863.7 ppb39,209
HannibalHannibal, MO6 of 6845.5 ppb17,916
City of Mesquite*Mesquite, TX8 of 8827.5 ppb143,350
City of GarlandGarland, TX8 of 8821.5 ppb236,786
City of Frisco*Frisco, TX8 of 8817.3 ppb192,261
City of RichardsonRichardson, TX8 of 8807.8 ppb104,300
City of Edgewater*Edgewater, FL4 of 4790.5 ppb23,626
City of AlamoAlamo, TX8 of 8788.9 ppb18,363
City of MaitlandMaitland, FL12 of 12787.5 ppb13,370
City of Port St. JoePort St. Joe, FL8 of 8777.5 ppb13,836
City of AllenAllen, TX8 of 8774.4 ppb102,762
N.S. MayportMayport, FL4 of 4765.7 ppb20,500
City of Richmond*Richmond, VA8 of 8765.0 ppb197,000
City of Weston (Indian Trace)Weston, FL4 of 4759.8 ppb54,620
Lake Utility Services Inc NorthClermont, FL23 of 23757.0 ppb21,518
Wellington Water Treatment PlantWellington, FL4 of 4756.0 ppb56,475
City of Coconut CreekCoconut Creek, FL4 of 4755.0 ppb54,000
Maynard DPW, Water DivisionMaynard, MA6 of 6746.7 ppb10,665
City of McKinney*Mckinney, TX8 of 8738.8 ppb169,710
Walnut Hill Water Authority*Dadeville, AL8 of 8732.5 ppb11,304
Alexander City Water Department*Alexander City, AL8 of 8732.5 ppb29,565
Lee County Utilities*Fort Myers, FL26 of 26732.0 ppb251,502
Gateway Services DistrictFort Myers, FL26 of 26732.0 ppb12,717
City of LemooreLemoore, CA10 of 10716.0 ppb24,945
Broward County Water and Wastewater Services (BCWWS) - 2A*Pompano Beach, FL4 of 4712.5 ppb54,622
Liberty*Liberty, MO4 of 4709.5 ppb31,507

* This water utility supplies finished drinking water to at least one other water utility. The purchasing utility is not required to test for or report Chlorate, but it likely has the contaminant in its water supply.