## Facts

- EPA promulgated the Safe Drinking Water Act’s “Lead and Copper Rule” to address lead contamination that often occurs after water leaves the treatment plant due to corrosion in service lines and plumbing materials.
- Instead of setting a numerical maximum contaminant level (MCL) for lead “at the tap,” EPA adopted a “treatment technique” approach requiring corrosion-control measures and, in some circumstances, replacement of lead service lines.
- EPA adopted an extended, phased compliance schedule for implementing lead-related treatment and other measures.
- EPA chose not to apply parts of the lead rule to transient noncommunity water systems (e.g., certain facilities where people do not regularly consume water over long periods).
- The rule required replacement of lead service lines that were part of distribution facilities “under the control” of a public water system, which EPA interpreted to include some line segments not owned by the water system.
- NRDC petitioned for review challenging the treatment-technique approach, the compliance schedule, and the exclusion of transient noncommunity systems.
- AWWA petitioned for review challenging EPA’s definition of “control” as applied to mandatory replacement of privately owned service lines.
- The consolidated petitions were reviewed by the D.C. Circuit.

## Issues

1. Whether the Safe Drinking Water Act required EPA to establish an MCL for lead at the tap rather than using a treatment technique.
2. Whether EPA’s extended compliance schedule violated the statute.
3. Whether EPA lawfully and adequately explained its decision not to regulate transient noncommunity water systems.
4. Whether EPA complied with APA notice-and-comment requirements when it defined distribution facilities “under the control” of a public water system to include certain privately owned service lines.

## Decision

- The court denied NRDC’s challenge to EPA’s use of a treatment technique, holding the statute permitted that approach where reliable monitoring for an MCL was not economically or technologically feasible.
- The court denied NRDC’s challenge to the extended compliance schedule, holding the schedule was not contrary to the statute.
- The court granted NRDC’s petition in part and remanded EPA’s exclusion of transient noncommunity water systems because the agency’s explanation was inadequate.
- The court granted AWWA’s petition and remanded the “control” definition because EPA did not provide adequate notice that it might adopt a broad interpretation reaching privately owned service lines.

## Legal Principles

- Under the Safe Drinking Water Act, EPA may prescribe a treatment technique instead of an MCL when determining and monitoring a reliable numerical level is not economically or technologically feasible.
- Courts generally defer to EPA’s technical judgments under the SDWA and the APA when supported by a reasoned administrative record.
- When an agency excludes a category from regulation, it must provide a reasoned explanation sufficient for judicial review under the APA.
- A final rule is procedurally defective under the APA if the notice of proposed rulemaking fails to give fair notice of a significant change in regulatory meaning (here, a broadened interpretation of “control” affecting privately owned service lines).

## Conclusion

The D.C. Circuit largely upheld EPA’s lead rule, including the choice of a treatment technique and a phased compliance schedule, but remanded two aspects: EPA’s insufficiently explained decision not to regulate transient noncommunity water systems and EPA’s broadened “control” definition adopted without adequate notice and opportunity for public comment.


Am. Water Works Ass’n v. EPA, 40 F.3d 1266 (D.C. Cir. 1994)