Class Certification and Predominance
A group of 4,200 homeowners sues a water utility over recurring discoloration and pressure loss, seeking damages and an injunction. Common issues include whether the utility's maintenance schedule was inadequate and whether its notices complied with regulations. Individual issues include how much each home's pipes contributed to discoloration, varying property damage amounts ($50 to $8,000), and differing durations of service. The named plaintiffs' homes had the worst damage. The utility opposes certification, arguing individual causation and damages swamp common questions. Plaintiffs propose a formula based on service records to calculate damages without individual proof. The court must rule on certification.
1. Apply the predominance requirement to these facts.
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Certification requires numerosity, commonality, typicality, adequacy, and-for damages-predominance plus superiority. Predominance asks whether common questions are more substantial than individual ones, not whether common questions merely exist.
Common questions: the adequacy of the maintenance schedule and regulatory notice compliance are genuinely common and could be resolved once for all 4,200 homes.
Individual questions: causation (each home's plumbing), damage amounts, and duration of service vary widely. Causation is the hard problem. If the utility's system-wide failure is the but-for cause for all class members, causation can be tried commonly. If each home's pipes are a competing cause, individual mini-trials dominate.
Conclusion: predominance is doubtful on damages and causation as pled, but the maintenance and notice issues are common. The court should scrutinize whether a system-wide theory can carry causation.
2. Can the proposed formula cure the damages problem, and how should the court rule?
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A formula can satisfy predominance only if it is grounded in the defendant's own records and does not require individualized inquiry into each class member's harm. Service records may establish duration and usage, which is a reasonable proxy for some damages. But if the formula cannot separate utility-caused discoloration from plumbing-caused discoloration, it does not solve causation-it merely assumes it.
Rule 23(b)(2) injunctive relief may be available for the prospective relief even if damages certification fails; the court can certify a liability/injunction class and deny the damages class, or certify an issue class on maintenance and notice.
Ruling: deny certification as to the damages class unless plaintiffs show a reliable common method of proving causation; grant certification for the injunctive-relief class. Typicality is also strained because the named plaintiffs' worst-case homes may not represent average members.