EWG's Tap Water Database — 2019 UPDATE



Status: National drinking water standard exists


Simazine is a hormone-disrupting herbicide related to atrazine. It affects the male and female reproductive systems. In studies of laboratory animals, simazine increases blood levels of estrogen, decreases prolactin and progesterone, and causes mammary and ovarian tumors.




states detected


utilities detected

18 million

people served


states over health guideline


utilities over health guideline


people served over health guideline

Health concerns for simazine

Harm to the developing fetus

Hormone disruption

Harm to the reproductive system

Changes in the nervous system

Changes in brain and behavior


State and national drinking water standards and health guidelines

EWG Health Guideline 0.1 ppb

The EWG Health Guideline of 0.1 ppb for simazine was defined by EWG based on epidemiological studies of human exposure to atrazine in drinking water. This health guideline protects against harm to the developing fetus, harm to the reproductive system and hormone disruption.

EPA Maximum Contaminant
Level (MCL) 4 ppb

The legal limit for simazine, established in 1992, was based on toxicity studies in laboratory animals conducted in the 1980s. This limit does not fully protect against harm to the reproductive system, harm to the developing fetus, and hormone disruption.

ppb = parts per billion

States reporting simazine in drinking water

State UtilitiesPeople Served UtilitiesPeople Served
District Of Columbia003648,882
North Carolina12550326,744
Rhode Island00467,053
New York158,000158,000
South Carolina0012,256
New Hampshire001233
New Mexico001120

Filtering technologies that reduce simazine

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Activated Carbon

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Reverse Osmosis

Utilities with the highest amounts of simazine, 2015-2017

UtilityLocationTestsAverage levelPeople served
Schram CityHillsboro, IL6 of 130.510 ppb700
Hillsboro*Hillsboro, IL6 of 130.510 ppb5,600
Taylor SpringsTaylor Springs, IL6 of 130.510 ppb600
CoffeenCoffeen, IL6 of 130.510 ppb709
Salem*Salem, IL2 of 110.442 ppb9,000
Jericho Water DistrictSyosset, NY35 of 740.396 ppb58,000
KinmundyKinmundy, IL2 of 50.376 ppb940
Pecan Grove MUD*Houston, TX4 of 200.338 ppb14,913
Fort Bend County Municipal Utility District 134dHouston, TX4 of 200.338 ppb105
Tritownship Water District*Highland, IL6 of 140.289 ppb3,620
TrentonTrenton, IL6 of 140.289 ppb2,832
FayettevilleFayetteville, IL6 of 140.289 ppb455
New Baden*New Baden, IL6 of 140.289 ppb3,552
SummerfieldSummerfield, IL6 of 140.289 ppb500
S L M Water Commission*Mascoutah, IL6 of 140.289 ppb300
LebanonLebanon, IL6 of 140.289 ppb4,541
Fsh Water Commission*Freeburg, IL6 of 140.289 ppb300
New Memphis Public Water DistrictNew Memphis, IL6 of 140.289 ppb938
MascoutahMascoutah, IL6 of 140.289 ppb7,110
White CityMount Olive, IL4 of 120.240 ppb350
Staunton Residential Road Water Co-opStaunton, IL4 of 120.240 ppb40
Mount Olive*Mount Olive, IL4 of 120.240 ppb2,150
Carlinville*Carlinville, IL3 of 120.213 ppb5,685
Lake Williamson Christian CenterCarlinville, IL3 of 120.213 ppb1,250
EvansvilleEvansville, IL2 of 120.213 ppb740
PatokaPatoka, IL3 of 120.211 ppb731
Fmc Water Company*Odin, IL3 of 120.211 ppb2,802
FarinaFarina, IL3 of 120.211 ppb600
Gateway Regional Water Company*Kinmundy, IL3 of 120.211 ppb1
VernonVernon, IL3 of 120.211 ppb176
XeniaXenia, IL3 of 120.211 ppb614
Flora*Flora, IL3 of 120.211 ppb5,675
Fort Bend County Municipal Utility District 58Houston, TX1 of 10.210 ppb4,488
SandovalSandoval, IL3 of 120.200 ppb1,760
Centralia*Centralia, IL3 of 120.200 ppb14,274
Pinwah Pines EstatesPflugerville, TX1 of 10.200 ppb130
WamacCentralia, IL3 of 120.200 ppb1,501
Walnut Hill*Walnut Hill, IL3 of 120.200 ppb1,566
Junction CityJunction City, IL3 of 120.200 ppb783
W G Murray Development CenterCentralia, IL3 of 120.200 ppb331
HoffmanHoffman, IL3 of 120.200 ppb525
Hoyleton RwcHoyleton, IL3 of 120.200 ppb1,147
Irvington*Irvington, IL3 of 120.200 ppb1,245
City of GrapevineGrapevine, TX2 of 30.197 ppb47,851
Decatur County Water CorporationGreensburg, IN5 of 120.187 ppb2,902
Greensburg Municipal Water Works*Greensburg, IN5 of 120.187 ppb12,000
Mattoon*Mattoon, IL3 of 120.176 ppb19,000
HumboldtHumboldt, IL3 of 120.176 ppb500
Fort Bend County Municipal Utility District 133Houston, TX1 of 10.170 ppb2,757
Breese*Breese, IL4 of 120.164 ppb4,192

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

UtilityLocationTestsAverage levelPeople served
Jericho Water DistrictSyosset, NY35 of 740.396 ppb58,000
Pecan Grove MUD*Houston, TX4 of 200.338 ppb14,913
Centralia*Centralia, IL3 of 120.200 ppb14,274
City of GrapevineGrapevine, TX2 of 30.197 ppb47,851
Greensburg Municipal Water Works*Greensburg, IN5 of 120.187 ppb12,000
Mattoon*Mattoon, IL3 of 120.176 ppb19,000
City of Sugar Land*Sugar Land, TX8 of 170.161 ppb83,886
Effingham*Effingham, IL2 of 100.141 ppb12,384
Piqua City PWSPiqua, OH6 of 180.139 ppb20,522
Newark City PWSNewark, OH2 of 170.128 ppb47,573
City of South HoustonSouth Houston, TX13 of 180.124 ppb13,578
City of LivingstonLivingston, TX2 of 30.123 ppb11,476
University ParkDallas, TX2 of 30.123 ppb24,396
Murphysboro*Murphysboro, IL9 of 130.119 ppb11,915
Harris County WCID 36Houston, TX4 of 70.117 ppb11,065
City of Texas CityTexas City, TX6 of 120.114 ppb48,558
Harris County FWSD 51*Houston, TX5 of 60.108 ppb10,401
Del-Co Water Company Inc.*Delaware, OH17 of 220.0959 ppb141,407
Speedway Water WorksSpeedway, IN2 of 90.0944 ppb11,812
Bexley City PWSBexley, OH10 of 190.0942 ppb13,650
Reynoldsburg City PWSReynoldsburg, OH10 of 190.0942 ppb35,893
Gahanna City PWSGahanna, OH10 of 190.0942 ppb33,323
Columbus Public Water System*Columbus, OH10 of 190.0942 ppb1,159,817
Johnston County - West*Wilson Mills, NC3 of 70.0941 ppb45,750
ClaytonClayton, NC3 of 70.0941 ppb14,030
Walpole Water DepartmentWalpole, MA7 of 110.0918 ppb23,997
Lafourche Water District 1Lockport, LA2 of 240.0917 ppb78,760
City of MonroeMonroe, NC4 of 120.0868 ppb30,135
Bedford City Utilities*Bedford, IN3 of 120.0850 ppb14,000
City of Midlothian*Midlothian, TX4 of 90.0811 ppb16,728
City of La MarqueLa Marque, TX1 of 30.0800 ppb15,154
City of Galveston*Galveston, TX1 of 30.0800 ppb50,180
Johnston County - East*Wilson Mills, NC5 of 100.0766 ppb24,310
Town of Smithfield*Smithfield, NC3 of 80.0701 ppb11,684
City of Galena ParkGalena Park, TX4 of 60.0700 ppb10,089
City of BellaireBellaire, TX4 of 70.0686 ppb22,473
Rathbun Regional Water Assn*Centerville, IA2 of 30.0667 ppb28,215
Remington MUD 1Houston, TX3 of 80.0663 ppb13,338
Fremont CityFremont, OH9 of 120.0658 ppb16,677
Newport Municipal Utility DistrictHouston, TX2 of 60.0650 ppb10,374
City of Waxahachie*Waxahachie, TX2 of 60.0650 ppb36,422
Harris County MUD 53Houston, TX8 of 150.0640 ppb16,164
City of ThomasvilleThomasville, NC2 of 50.0628 ppb26,418
Galveston County WCID 1Dickinson, TX5 of 90.0622 ppb29,280
Stucker Fork Water Utility*Scottsburg, IN3 of 120.0592 ppb18,873
City of Grand Prairie*Grand Prairie, TX3 of 210.0576 ppb187,050
City of La PorteLa Porte, TX12 of 240.0567 ppb34,733
Clear Lake City Water Authority*Houston, TX4 of 120.0550 ppb85,636
City of Baytown*Baytown, TX2 of 30.0533 ppb72,312
Harris County MUD 102Houston, TX2 of 40.0500 ppb10,212

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