Know Your Environment. Protect Your Health.

Atrazine

Regional Water Authority

Atrazine is a herbicide commonly detected in drinking water that comes from cornfield and other agricultural runoff. It is a hormone disrupter that harms the male and female reproductive systems of people and wildlife. Read More.

Federal laws allow up to 3 parts per billion of atrazine in treated tap water. Water suppliers average atrazine measurements collected over a year, which means that the reported values underestimate intense spikes of elevated exposures during the periods in late spring and early summer when atrazine is applied in large amounts on farm fields.

Human epidemiological studies suggest that federal standards for atrazine are insufficient to protect public health. In 1999 the California Office of Environmental Health Hazard Assessment set a public health goal of 0.15 parts per billion for atrazine in drinking water, based on a study finding increased rates of breast cancer in rats exposed to the chemical. California’s legal maximum for atrazine in tap water is 1 ppb.

Click here to read more about atrazine.

 

54

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2018N/A00N/A
2019ND220ND
2020N/A00N/A
2021N/A00N/A
2022ND320ND
2023N/A00N/A

ppb = parts per billion

State, National, and Health Guidelines for Drinking Water

EWG Health Guideline: 0.1 ppb

The EWG Health Guideline of 0.1 ppb for atrazine 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): 3 ppb

The legal limit for atrazine, established in 1991, was based on a toxicity study 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

All test results

Date Lab ID Result
2019-05-08SOC 200531300ND
2019-05-28SOC 200533720ND
2019-05-28SOC 200533719ND
2019-05-28SOC 200533803ND
2019-05-28SOC 200533804ND
2019-05-28SOC 200533660ND
2019-05-28SOC 200533659ND
2019-05-29SOC 200533881ND
2019-05-29SOC 200533880ND
2019-05-29SOC 200533867ND
2019-05-29SOC 200533868ND
2019-08-26SOC 200546197ND
2019-08-26SOC 200546198ND
2019-08-26SOC 200546200ND
2019-08-27SOC 200546267ND
2019-08-27SOC 200546303ND
2019-08-27SOC 200546302ND
2019-08-27SOC 200546268ND
2019-08-28SOC 200546738ND
2019-08-28SOC 200546737ND
2019-08-28SOC 200546736ND
2019-08-28SOC 200546553ND
2022-07-11S300210822 300210824ND
2022-07-11S300210156 300210158ND
2022-07-11S300210164 300210166ND
2022-07-11S300210651 300210653ND
2022-07-11S300210659 300210661ND
2022-07-12S300211086 300211088ND
2022-07-12S300211076 300211078ND
2022-07-12S300211068 300211070ND
2022-07-13S300212413 300212415ND
2022-07-13S300212421 300212423ND
2022-07-14S300212957 300212959ND
2022-10-17S300258850 300258852ND
2022-10-17300258850 300258852BND
2022-10-17300258858 300258860BND
2022-10-17S300258858 300258860ND
2022-10-18S300259358 300259360ND
2022-10-18S300258921 300258923ND
2022-10-18300258921 300258923BND
2022-10-18300259358 300259360BND
2022-10-18S300259350 300259352ND
2022-10-18300259350 300259352BND
2022-10-18300258913 300258915BND
2022-10-18S300258913 300258915ND
2022-10-19S300259930 300259934ND
2022-10-19300259930 300259934BND
2022-10-19300259940 300259942BND
2022-10-19S300259940 300259942ND
2022-10-19S300260499 300260501ND
2022-10-19300260499 300260501BND
2022-10-19300260507 300260509BND
2022-10-19S300260507 300260509ND
2022-12-06S300281400 300281402ND