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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.

2010-2015:

FOUND
FOUND ABOVE HEALTH GUIDELINES

50

states detected

6,757

utilities detected

208 million

people served

45

states over health guideline

1,732

utilities over health guideline

46 million

people served over health guideline

Health concerns for chlorate

Hormone disruption

State and national drinking water standards and health guidelines

Health Guideline 210 ppb

The 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
California1037,893,93156039,972,896
New York26654,57827317,784,115
Texas2433,902,50074416,828,024
Florida23910,239,32333615,806,691
New Jersey28710,7252258,224,891
Pennsylvania151,747,7842477,294,569
Ohio46823,9252106,726,310
North Carolina1372,172,1233955,887,762
Virginia883,276,1281415,790,477
Georgia471,555,6951755,684,964
Massachusetts35943,7021815,427,669
Arizona13155,4861365,313,752
Maryland12241,834474,875,839
Tennessee51963,1571744,329,096
Washington596,4312014,312,815
Alabama1001,366,8352304,144,789
Illinois49456,4072723,769,304
Kentucky62936,7612013,399,999
Colorado17547,2831363,196,532
South Carolina711,034,2561712,795,875
Connecticut14122,148712,478,634
Nevada00212,423,721
Wisconsin8100,724812,296,938
Oregon20687,309782,293,492
Missouri33348,852852,217,129
Indiana281,176,579622,171,053
Louisiana28954,161862,150,872
Michigan12177,0571102,002,382
Utah00551,722,702
Oklahoma69464,7471751,623,873
Kansas17163,257811,371,225
Iowa18184,6791651,360,244
Arkansas16365,6681231,333,935
Minnesota678,458371,250,846
New Mexico355,102361,222,104
Hawaii11,310171,199,784
Nebraska00241,084,110
Delaware6154,60616682,329
Idaho0018664,632
District Of Columbia5664,5725664,572
West Virginia234,31178621,202
New Hampshire9152,78047600,753
Rhode Island351,99824568,036
Mississippi457,16220514,014
Alaska8131,13123430,367
Maine445,77821416,576
South Dakota0058381,641
Vermont18167,53737232,664
Wyoming1161,06535226,163
Montana120,0089176,234
North Dakota179241,317
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Utilities with the highest amounts of chlorate, 2010-2015

ALL UTILITIES
LARGE UTILITIES
UtilityLocationTestsAverage levelPeople served
Vc/halifax Plantation (wtp-8)Ormond Beach, FL4 of 42,530.0 ppb4,419
Danvers Water Department*Middleton, MA12 of 122,057.5 ppb35,480
City of Bonham*Bonham, TX8 of 82,031.9 ppb10,005
Oak Shores Water SystemMontague, TX3 of 41,867.5 ppb228
VC/Southwest Water SystemOrange City, FL12 of 121,735.0 ppb16,976
Savage*Savage, MN3 of 61,687.7 ppb26,911
AtkinsonAtkinson, IL4 of 41,432.9 ppb1,001
Willingboro MUA*Willingboro, NJ8 of 81,379.0 ppb35,000
Pennsville Twsp. Water Depart.Pennsville, NJ7 of 81,316.4 ppb13,500
Garden City*Garden City, MO7 of 71,211.4 ppb1,642
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 ppb1,929
Seminole County Northeast*Lake Mary, FL8 of 81,052.7 ppb18,462
St. MarysSt. Marys, GA5 of 61,047.7 ppb17,270
City of Terrell*Terrell, TX8 of 81,040.9 ppb17,665
Alco Water ServiceSalinas, CA6 of 71,021.7 ppb29,179
Westside Rural Water Supply CorporationPflugerville, TX10 of 121,009.2 ppb855
City of Goldsboro*Goldsboro, NC8 of 81,007.0 ppb36,306
City of WylieWylie, TX8 of 81,006.9 ppb41,043
City of Forney*Forney, TX8 of 8989.6 ppb16,800
Okeechobee Utility AuthorityOkeechobee, FL12 of 12986.6 ppb20,000
Harris County WCID 36*Houston, TX6 of 20985.3 ppb11,065
Des Plaines Mobile Home ParkSanta Ana, IL4 of 4968.5 ppb340
CentralWinter Haven, FL17 of 17968.2 ppb13,595
University of Central FloridaOrlando, FL4 of 4946.5 ppb57,500
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
City of McFarlandMcfarland, CA15 of 16916.7 ppb12,333

* 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.

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UtilityLocationTestsAverage levelPeople served
Danvers Water Department*Middleton, MA12 of 122,057.5 ppb35,480
City of Bonham*Bonham, TX8 of 82,031.9 ppb10,005
VC/Southwest Water SystemOrange City, FL12 of 121,735.0 ppb16,976
Savage*Savage, MN3 of 61,687.7 ppb26,911
Willingboro MUA*Willingboro, NJ8 of 81,379.0 ppb35,000
Pennsville Twsp. Water Depart.Pennsville, NJ7 of 81,316.4 ppb13,500
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 Northeast*Lake Mary, FL8 of 81,052.7 ppb18,462
St. MarysSt. Marys, GA5 of 61,047.7 ppb17,270
City of Terrell*Terrell, TX8 of 81,040.9 ppb17,665
Alco Water ServiceSalinas, CA6 of 71,021.7 ppb29,179
City of Goldsboro*Goldsboro, NC8 of 81,007.0 ppb36,306
City of WylieWylie, TX8 of 81,006.9 ppb41,043
City of Forney*Forney, TX8 of 8989.6 ppb16,800
Okeechobee Utility AuthorityOkeechobee, FL12 of 12986.6 ppb20,000
Harris County WCID 36*Houston, TX6 of 20985.3 ppb11,065
CentralWinter Haven, FL17 of 17968.2 ppb13,595
University of Central FloridaOrlando, FL4 of 4946.5 ppb57,500
Broward County Water and Wastewater Services (BCWWS) - 1ALauderdale Lakes, FL4 of 4935.0 ppb75,305
City of McFarlandMcfarland, CA15 of 16916.7 ppb12,333
Charleston*Charleston, IL8 of 8914.6 ppb15,500
Town of Little ElmLittle Elm, TX6 of 6897.7 ppb27,468
Windermere Community*Pflugerville, TX24 of 24896.1 ppb18,777
Poplar BluffPoplar Bluff, MO16 of 16883.4 ppb17,000
New Mexico State UniversityLas Cruces, NM10 of 10865.4 ppb24,302
Southwest/Polk County UtilityLakeland, FL20 of 20863.7 ppb39,209
City of Mesquite*Mesquite, TX8 of 8827.5 ppb143,484
City of Garland*Garland, TX8 of 8821.5 ppb234,533
City of Frisco*Frisco, TX8 of 8817.3 ppb136,493

* 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.

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