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EWG's Tap Water Database — 2021 UPDATE

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Diquat

Status: National drinking water standard exists

 

Diquat is a herbicide used on potato crops and aquatic weeds.

2017-2019:

FOUND
FOUND ABOVE HEALTH GUIDELINES

11

states detected

96

utilities detected

2.0 million

people served

0

states over health guideline

0

utilities over health guideline

0

people served over health guideline

Health concerns for diquat

Change to fetal growth and development

Change in body weight

Harm to the kidney

Cataracts

State and national drinking water standards and health guidelines

EWG Health Guideline 6 ppb

The EWG Health Guideline of 6 ppb for diquat was defined by the California Office of Environmental Health Hazard Assessment as a public health goal, the level of a drinking water contaminant that does not pose a significant health risk. This health guideline protects against cataracts.

EPA Maximum Contaminant
Level (MCL) 20 ppb

The legal limit for diquat, established in 1992, was based on a toxicity study in laboratory animals conducted in the 1980s.

ppb = parts per billion

States reporting diquat in drinking water

UTILITIES WITH CONTAMINATION
State UtilitiesPeople Served
Texas161,070,152
Florida23782,742
Iowa3564,677
Louisiana328,010
Oklahoma723,225
Arizona420,778
Arkansas114,106
New Hampshire39,646
Wyoming21,780
Wisconsin148
Pennsylvania138
MORE
LESS

Filtering technologies that reduce diquat

Activated Carbon

Reverse Osmosis

Utilities with the highest amounts of diquat, 2017-2019

ALL UTILITIES
LARGE UTILITIES
UtilityLocationTestsAverage levelPeople served
Lycoming Creek VillageWilliamsport, PA1 of 53.24 ppb38
Autumn WoodsDerry, NH1 of 11.90 ppb73
Milford Water Utilities Department*Milford, NH1 of 21.85 ppb9,500
Ashley CommonsMerrimack, NH1 of 21.85 ppb73
Frostproof, City ofFrostproof, FL2 of 121.27 ppb3,550
Mid-tex UtilitiesPflugerville, TX2 of 70.714 ppb945
City of Austin Water & Wastewater*Austin, TX2 of 70.714 ppb981,783
City of Sunset ValleySunset Valley, TX2 of 70.714 ppb1,485
City of RollingwoodRollingwood, TX2 of 70.714 ppb1,611
Marsha Water Supply CorporationAustin, TX2 of 70.714 ppb480
Northtown MUDAustin, TX2 of 70.714 ppb11,520
Hill Oaks Mobile EstatesAustin, TX2 of 70.714 ppb168
Wells Branch MUD 1Austin, TX2 of 70.714 ppb22,062
North Austin Municipal Utility District 1Austin, TX2 of 70.714 ppb11,133
Rivercrest Water System*Austin, TX2 of 70.714 ppb1,437
Nighthawk Water Supply CorporationAustin, TX2 of 70.714 ppb396
Travis County Water Control and Improvement District 10West Lake Hills, TX2 of 70.714 ppb8,913
High Valley Water Supply CorporationAustin, TX2 of 70.714 ppb231
Woodbridge EstatesMadison, WI1 of 10.680 ppb48
Empirita Water CompanyTucson, AZ1 of 30.667 ppb82
Davis*Davis, OK3 of 70.571 ppb2,610
City of HialeahHialeah, FL1 of 100.520 ppb240,000
Dragoon Water CompanyTucson, AZ2 of 80.500 ppb317
Lake TippecanoeSarasota, FL1 of 50.500 ppb377
Mescal Lakes Water SystemTucson, AZ2 of 80.500 ppb1,479
Ruskin MobilesRuskin, FL1 of 70.486 ppb36
Start Water SystemStart, LA2 of 80.475 ppb2,514
FletcherFletcher, OK2 of 30.467 ppb1,022
CentralWinter Haven, FL1 of 200.380 ppb13,595
Adel Municipal Water WorksAdel, IA1 of 10.368 ppb3,690
Superior, Town OfSuperior, WY1 of 40.308 ppb356
Lexington & Joseph Harp Correctional InstitutionLexington, OK6 of 360.281 ppb3,000
Antelope Valley I&s DistrictGillette, WY1 of 30.280 ppb1,280
Lansing Water SupplyLansing, IA1 of 10.256 ppb999
Hot Springs Village WaterworksHot Springs Village, AR1 of 110.209 ppb14,106
St. Lucie Mobile VillageIndiantown, FL1 of 20.200 ppb750
Sheppard Air Force BaseSheppard Afb, TX2 of 80.175 ppb19,500
City of Wichita Falls*Wichita Falls, TX2 of 80.175 ppb104,553
City of HollidayHolliday, TX2 of 80.175 ppb1,758
City of ScotlandScotland, TX2 of 80.175 ppb850
Archer County Municipal Utility District 1Wichita Falls, TX2 of 80.175 ppb1,221
City of Lakeside CityWichita Falls, TX2 of 80.175 ppb1,100
Horseshoe Bend EstatesIowa Park, TX2 of 80.175 ppb100
City of Iowa Park*Iowa Park, TX2 of 80.175 ppb6,355
Town of Pleasant ValleyIowa Park, TX2 of 80.175 ppb330
Friberg-cooper Water Supply CorporationWichita Falls, TX2 of 80.175 ppb918
Polk Correctional InstitutionPolk City, FL1 of 20.155 ppb1,500
Marquette Water SupplyMarquette, IA1 of 20.154 ppb462
Ruth Water DistrictMcgill, NV1 of 150.153 ppb470
Ely Municipal Water Department*Ely, NV1 of 150.153 ppb5,000

* 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 Diquat, but it likely has the contaminant in its water supply.

UtilityLocationTestsAverage levelPeople served
Northtown MUDAustin, TX2 of 70.714 ppb11,520
Wells Branch MUD 1Austin, TX2 of 70.714 ppb22,062
North Austin Municipal Utility District 1Austin, TX2 of 70.714 ppb11,133
City of Austin Water & Wastewater*Austin, TX2 of 70.714 ppb981,783
City of HialeahHialeah, FL1 of 100.520 ppb240,000
CentralWinter Haven, FL1 of 200.380 ppb13,595
Hot Springs Village WaterworksHot Springs Village, AR1 of 110.209 ppb14,106
Sheppard Air Force BaseSheppard Afb, TX2 of 80.175 ppb19,500
City of Wichita Falls*Wichita Falls, TX2 of 80.175 ppb104,553
Windermere CommunityPflugerville, TX5 of 270.144 ppb20,091
Central IA Water Assn (Waverly)*Newton, IA1 of 20.0950 ppb34,245
City of Temple Terrace UtilityTemple Terrace, FL1 of 140.0705 ppb31,250
Manatee County Utilities Department*Bradenton, FL1 of 160.0606 ppb447,382
Palmetto Water DepartmentPalmetto, FL1 of 160.0606 ppb12,606
Beauregard Water Works District #3Dry Creek, LA2 of 460.0374 ppb21,600
City of HendersonHenderson, NV1 of 140.0343 ppb321,781
City of Pineville Water SystemPineville, LA2 of 440.0305 ppb20,315
City of Buckeye Sonora - SundanceBuckeye, AZ1 of 140.0236 ppb15,783
Miramar (East & West) PlantsMiramar, FL1 of 160.0188 ppb127,700
City of SaffordSafford, AZ1 of 300.0187 ppb18,900
Gateway Services DistrictFort Myers, FL1 of 260.0154 ppb12,717
Lee County Utilities*Fort Myers, FL1 of 260.0154 ppb251,502

* 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 Diquat, but it likely has the contaminant in its water supply.