## Facts

- Stormwater runoff was a major source of water pollution, and Congress addressed it through the Clean Water Act (CWA) National Pollutant Discharge Elimination System (NPDES) permitting program.
- In 1999, EPA issued the “Phase II” stormwater rule requiring NPDES permit coverage for (1) “small” municipal separate storm sewer systems (MS4s), particularly those in urbanized areas, and (2) construction sites disturbing one to five acres.
- For small MS4s, the rule generally allowed coverage under general permits. Operators seeking coverage commonly filed a notice of intent (NOI) describing how they would meet six “minimum measures” (e.g., public education, public involvement, illicit discharge detection and elimination, controls for construction and post-construction runoff, and municipal operations/good housekeeping).
- The rule also allowed an “alternative-program” option under which an MS4 could seek permit coverage by proposing a stormwater management program addressing similar concerns, without necessarily implementing the six minimum measures as written.
- Under EPA’s approach, the NOI often contained the operator-specific stormwater controls and schedules that effectively defined what the operator would do to limit pollutants, yet the rule did not require the permitting authority to review each NOI before coverage became effective or to provide public notice and a hearing opportunity tied to the NOI’s substantive content.
- Municipal, environmental, and industry petitioners filed challenges in multiple circuits; the petitions were consolidated in the Ninth Circuit for review of the Phase II rule.
- Among other arguments, municipal petitioners asserted the rule violated the Tenth Amendment by compelling local governments to regulate third parties (such as developers and private landowners) as a condition of MS4 permit compliance.

## Issues

1. Whether the Phase II rule’s small MS4 general-permit/NOI structure satisfied the CWA’s NPDES requirements when the NOI contained operator-specific stormwater controls.
2. Whether the rule violated the CWA’s public participation requirements by allowing NOIs (with operative pollution-control commitments) to take effect without mandated public availability and an opportunity for hearing.
3. Whether EPA acted arbitrarily or contrary to the CWA by failing to address stormwater discharges associated with forest roads under its Phase II authority.
4. Whether the Phase II rule, on its face, violated the Tenth Amendment by effectively requiring state and local governments operating MS4s to regulate third parties.
5. Whether EPA acted within its statutory authority in designating small MS4s in urbanized areas and one-to-five-acre construction sites for NPDES permitting.

## Decision

- The Ninth Circuit granted the consolidated petitions in part and denied them in part.
- The court rejected the facial Tenth Amendment challenge, concluding the rule conditioned the right to discharge on obtaining federal permit coverage and did not compel state or local governments to administer a federal program.
- The court upheld EPA’s general decision to regulate small MS4s and one-to-five-acre construction sites under Phase II and sustained much of the overall regulatory framework.
- The court held that where NOIs contain substantive pollution-control programs that function as permit terms, EPA’s rule could not lawfully allow those NOIs to become effective without permitting-authority oversight and without making them available for public review with an opportunity for a hearing.
- The court vacated and remanded the portions of the Phase II rule that failed to require adequate review and public availability of NOIs containing substantive control measures.
- The court also remanded EPA’s approach to stormwater discharges from forest roads, concluding EPA had not provided a reasoned basis, consistent with the statute and record, for declining to address that category under its Phase II authority.

## Legal Principles

- The CWA’s NPDES program relies on permit conditions that are enforceable and subject to public availability and, where appropriate, a hearing opportunity.
- A submission labeled as an NOI may trigger CWA public participation requirements when it supplies the operator-specific pollution-control measures that effectively define permit obligations.
- EPA may use general permits for stormwater, but it may not structure a program so that core, operator-specific permit terms are set through unreviewed, non-public submissions.
- Under CWA § 402(p)(6), EPA has discretion to designate additional stormwater sources for regulation, but the agency must give a reasoned explanation for excluding or declining to address a significant discharge category raised by the record.
- Conditioning permission to discharge pollutants on meeting federal requirements is not, by itself, unconstitutional commandeering; regulated entities may choose not to discharge rather than accept permit conditions.

## Conclusion

Environmental Defense Center, Inc. v. U.S. EPA upheld most of EPA’s 1999 Phase II stormwater rule, including EPA’s authority to designate small MS4s and small construction sites for NPDES permitting and the rule’s compatibility with the Tenth Amendment, but it vacated and remanded the small MS4 NOI/public-participation provisions and required EPA to reconsider, with a reasoned explanation, its treatment of stormwater discharges from forest roads.


Environmental Defense Center, Inc. v. United States Environmental Protection Agency, 344 F.3d 832 (2003)