Atrazine in Well Water: Herbicide Limits and Testing
Short answer: atrazine is a herbicide used mostly on corn. EPA's limit for public water is 3 µg/L. Health Canada's is 5 µg/L for atrazine plus its breakdown products.
Who should test
Wells near cropland, especially shallow wells, or wells with high nitrate, which also comes from farm runoff. Health Canada lists leaching and runoff from farm use as the source and says it persists in water.
How to test
Ask for atrazine by EPA method 525.2/525.3 or 507, or a pesticide panel that includes it. Some state labs offer a triazine screen.
What results mean
Above the limit: retest, and look at activated carbon treatment certified for atrazine. Also see pesticides in well water.
Sources
- EPA: National Primary Drinking Water Regulations
- Health Canada: Guidelines for Canadian Drinking Water Quality, summary table (Dec 2025)
Questions
What is the EPA limit for atrazine?
3 µg/L (0.003 mg/L) for public water systems.
Is Canada's limit different?
Yes. Health Canada's maximum is 5 µg/L and applies to atrazine plus its breakdown products.
Is atrazine in a standard well test?
No. Ask for it by name or a pesticide panel that includes it.
Free well water checklist
15 family-friendly steps based on CDC and EPA guidance. Print it, keep it on the fridge, and know when to call a certified lab.
More guides
- FHA, VA and USDA Loan Well Water Test RequirementsLoan rules for well water tests, side by side, from HUD, VA and USDA handbooks.
- Mail-In vs Drop-Off Well Water Testing: Which to ChooseThe 30-hour bacteria clock, and which tests travel well by mail.
- How Much Does Well Water Testing Cost? Real Lab PricesReal published prices from public labs, free programs, and the EPA-approved-lab myth.
- Testing Tap, Spring, Lake, River or Pond WaterTap, spring, lake, river and pond water: where to test, and why pools and aquariums are different.