News Feature | January 7, 2026

EPA Proposes New Rule To Address Perchlorate In Drinking Water

Outside US EPA Building

The U.S. EPA has unveiled a comprehensive proposal to establish a National Primary Drinking Water Regulation (NPDWR) for perchlorate — a chemical linked to thyroid disruption — marking the culmination of a legal mandate stemming from a 2023 D.C. Circuit Court ruling in NRDC v. Regan. The court ordered the agency to regulate perchlorate after EPA attempted to withdraw earlier efforts, declaring no standard necessary. The move restores regulatory oversight under the Safe Drinking Water Act and follows a landmark consent decree requiring a proposal by January 2, 2026, and a final rule by May 21, 2027.

Health-Based Goals And Enforceable Limits

In its proposal published January 6, 2026, in the Federal Register (91 FR 398), the EPA recommends setting the health-based Maximum Contaminant Level Goal (MCLG) at 0.02 mg/L (20 µg/L). The agency is also seeking public comment on establishing enforceable Maximum Contaminant Levels (MCLs) at 20, 40, or 80 µg/L. These benchmarks aim to protect sensitive populations — especially fetuses, infants, and pregnant women — by safeguarding thyroid hormone production vital for infant brain development.

Monitoring, Reporting, And Mitigation

Under the proposal, approximately 66,000 Community and Non‑Transient Non‑Community Water Systems would be required to regularly monitor perchlorate levels. The framework, derived from the Agency’s Standardized Monitoring Framework for inorganic contaminants, allows reductions in monitoring frequency based on initial results to lessen administrative burdens. If perchlorate levels exceed the chosen MCL, water systems must implement mitigation measures, notify consumers (via public notices and Consumer Confidence Reports), and report to their state primacy agency. A compliance timeline gives utilities three years after the final rule’s publication to complete initial monitoring.

EPA’s Perspective And Cost–Benefit Analysis

EPA officials reaffirmed that they are advancing this rule not out of conviction over its necessity, but to comply with judicial directive. The agency’s cost‑benefit analysis acknowledges that while perchlorate may not be widespread, monitoring across tens of thousands of systems could impose “substantial administrative and monitoring costs” with comparatively limited public health benefits. The proposal candidly states that although mandating an MCLG and MCL is legally required, the positive impacts on overall public health may not justify the expense.

Public Engagement And Next Steps

The official public comment period is open until March 9, 2026, with virtual hearings scheduled for February 19, 2026, where stakeholders — including utilities, states, and public interest groups — can voice concerns or support. Submission of comments on data collection aspects must also go to the Office of Management and Budget by February 5, 2026. Following the period for inputs, EPA will review comments and draft a final rule set to be released by the May 21, 2027 deadline.

Expert And Industry Reactions

  • Association of Metropolitan Water Agencies (AMWA) CEO Tom Dobbins acknowledged the Agency’s use of updated science and stated AMWA’s intent to thoroughly review the proposal for practicality and health protection. He emphasized that any regulations should be “practical, achievable, and protective of public health,” and urged avoiding “unnecessary, expensive mandates” for utilities and ratepayers.
  • The Perchlorate Information Bureau (PIB) praised the EPA's reliance on what it called “the best available scientific information,” asserting that environmental levels pose no threat even to sensitive groups. They highlighted that most U.S. detections are below 10 ppb — far beneath proposed thresholds — and argued that federal regulation is unwarranted given state-level actions and decreasing perchlorate levels.
  • NRDC issued a mixed yet critical response. Sarah Fort, a senior attorney, emphasized that “members of the public deserve to know whether there's rocket fuel in their tap water,” welcoming the EPA's action — albeit “reluctant.” However, NRDC senior strategic director Erik D. Olson cautioned that the proposed 20 µg/L maximum contaminant level is “weak,” noting that it is far less protective than existing state standards and poses risks to vulnerable populations, especially infants and fetuses.