EPA legal limit
3 ppb
Maximum Contaminant Level
EWG health guideline
0.1 ppb
Science-based, stricter target
IARC classification
Group 2B
Cancer research classification
Health effects
Atrazine is an endocrine disruptor — it interferes with hormone function. Animal studies show reproductive and developmental effects at low concentrations. The EWG health guideline of 0.1 ppb is 30× more protective than the EPA MCL of 3 ppb.
Where it comes from
Agricultural runoff from corn and sorghum fields. Highest concentrations found in Midwest drinking water systems, particularly in spring and early summer following application season.
How it's regulated
EPA MCL of 3 ppb. The EWG health guideline of 0.1 ppb is based on reproductive effects in animal studies. Atrazine's registration for use in the U.S. is periodically reviewed by EPA.
The EPA vs EWG gap
The legal limit (3 ppb) is 30× higher than the EWG health guideline (0.1 ppb). Water can be legally compliant while still exceeding the science-based threshold.
How to filter atrazine
Not all filters address atrazine. Look for independently certified filters—NSF International certification means the removal claim has been independently verified.
Frequently asked questions
What is atrazine?
One of the most widely used herbicides in the United States, applied to corn, sorghum, and sugarcane. Among the most commonly detected pesticides in U.S. drinking water, particularly in the Corn Belt.
What are the health effects of atrazine?
Atrazine is an endocrine disruptor — it interferes with hormone function. Animal studies show reproductive and developmental effects at low concentrations. The EWG health guideline of 0.1 ppb is 30× more protective than the EPA MCL of 3 ppb.
Is atrazine regulated in drinking water?
EPA MCL of 3 ppb. The EWG health guideline of 0.1 ppb is based on reproductive effects in animal studies. Atrazine's registration for use in the U.S. is periodically reviewed by EPA.
Where does atrazine come from?
Agricultural runoff from corn and sorghum fields. Highest concentrations found in Midwest drinking water systems, particularly in spring and early summer following application season.
How do I remove atrazine from tap water?
The most effective methods for removing atrazine are: Activated carbon block filter, NSF 53 certified filter, Reverse osmosis (RO). Look for NSF-certified systems—independent certification confirms removal claims have been verified.
Is atrazine in your water?
Enter your ZIP code to see the measured level in your specific utility.