## Facts

- Homestake Mining Company operated gold-mining facilities in South Dakota and indirectly discharged mining wastes to a creek.
- South Dakota revised its water-quality standards and designated the receiving creek as a “cold water permanent fishery,” triggering more stringent criteria.
- EPA reviewed and approved South Dakota’s revised standards.
- EPA Region VIII issued Homestake an NPDES permit under Clean Water Act § 402 that incorporated the state standards and related limits.
- Homestake sued EPA and South Dakota, seeking to invalidate (i) the fishery designation and revised standards and (ii) the resulting NPDES permit conditions.
- The case was submitted on cross-motions for summary judgment.

## Issues

1. Whether EPA’s approval of South Dakota’s revised water-quality standards, including the “cold water permanent fishery” designation, was arbitrary and capricious or otherwise unlawful.
2. Whether the NPDES permit was invalid because EPA had not completed other statutory duties under the Clean Water Act before issuing the permit.
3. Whether the Clean Water Act permits states, with EPA approval, to impose water-quality standards more stringent than federal technology-based minimums and enforce them through NPDES permits.

## Decision

- The court granted summary judgment for EPA and South Dakota and denied Homestake’s motion.
- The court upheld EPA’s approval of South Dakota’s revised water-quality standards, including the cold-water fishery designation.
- The court upheld Homestake’s NPDES permit conditions incorporating the approved state standards.
- The court held EPA’s actions were within statutory authority and not arbitrary or capricious.

## Legal Principles

- Clean Water Act § 301(a) generally prohibits pollutant discharges unless authorized by the Act, chiefly through NPDES permits under § 402.
- The Act establishes technology-based effluent limits as a minimum baseline, but permits may also include more stringent limits necessary to meet applicable water-quality standards.
- States may adopt or enforce standards and limitations more stringent than federal requirements under Clean Water Act § 510; federal law does not bar stricter state water-quality classifications and criteria.
- EPA may approve state water-quality standards that exceed federal minima if they satisfy statutory requirements, and such standards may be applied through NPDES permits.
- Under APA arbitrary-and-capricious review, EPA’s approval of state standards is upheld if EPA considered relevant factors and made a reasoned decision within its delegated authority.
- EPA may issue NPDES permits during periods when other agency-wide statutory tasks are not yet fully completed; incomplete implementation of unrelated duties does not, by itself, invalidate a permit.

## Conclusion

The court sustained the Clean Water Act’s state–federal structure by upholding EPA’s approval of South Dakota’s stricter water-quality classification and EPA’s incorporation of those standards into Homestake’s NPDES permit, rejecting claims of arbitrariness and of invalidity based on unfinished agency program obligations.


Homestake Mining Co. v. United States Environmental Protection Agency, 477 F. Supp. 1279 (D.S.D. 1979)