Groups sue EPA over atrazine pollution in US waterways
The story at a glance
Three groups filed suit against the US Environmental Protection Agency on 14 October 2026. They want a court to require the agency to set Clean Water Act water-quality criteria for atrazine.1
The case concerns a reported freshwater pollution problem, but the requested action remains a legal claim for future regulatory steps. EPA has a separate pesticide-registration review under way.12
The story in brief
What you need to know
- The plaintiffs are the Center for Biological Diversity, Center for Environmental Health and Pesticide Action & Agroecology Network. Their complaint asks for an order requiring EPA to issue proposed and final atrazine criteria under the Clean Water Act.1
- The complaint alleges EPA began developing Clean Water Act criteria in 1999 but has not finalised them. Whether the agency has failed a legal duty or unlawfully delayed action has not been decided by a court.14
- A September 2026 analysis by the Center for Biological Diversity estimates that harmful atrazine levels occur in more than 25% of river and stream miles in the lower 48 states, nearly 860,000 miles. The figure is the organisation’s estimate, not an independently reproduced national result.3
- The Center’s analysis also says affected watersheds supply more than 20% of surface-water drinking-water facilities and contain at least 675,000 wells. Separately, USGS monitoring identifies atrazine among the pesticides posing the greatest threats to surface water.3
- EPA’s separate pesticide-registration review includes proposed mitigation measures and a revised concentration level of concern for aquatic plants. These steps are distinct from final Clean Water Act water-quality criteria.2
Conservation context
Why this matters
Atrazine levels that may harm aquatic wildlife are the focus of both the lawsuit and the Center’s estimate of widespread contamination. The reported presence of atrazine in watersheds serving drinking-water facilities and containing wells also gives the issue relevance beyond river ecology.13
The developing story
What happens next
The court will consider the plaintiffs’ claims, but the sources reviewed do not establish a ruling or outcome. At the time of KUNC’s report, EPA had not filed a response and declined to comment on the pending litigation.4
Established evidence
What we know
- The complaint seeks proposed and final Clean Water Act criteria for atrazine.1
- The nationwide river-mile estimate comes from a September 2026 analysis by the Center for Biological Diversity, based on EPA monitoring and modelling records.3
- EPA’s pesticide-registration review and its work on Clean Water Act criteria are separate regulatory processes.12
Open questions
What we don't know
- How the court will rule on the plaintiffs’ legal claims, or how EPA will respond to the complaint.4
- The methods, thresholds and uncertainty ranges behind the Center’s estimate of harmful atrazine levels across nearly 860,000 river and stream miles.3
- Whether EPA will finalise the separate registration-review measures, or what effect they would have on atrazine concentrations in waterways.2
Source coverage
