The National Association of Clean Water Agencies and Wet Weather Partnership are weighing in on a court decision that they claim may hamper cleaning up the nation's waters. The groups filed a brief Aug. 25 backing a District of Columbia Water and Sewer Authority petition to the Supreme Court. WASA wants the high court to review an April 25 D.C. Circuit appellate court ruling that a strict reading of total maximum daily loads under the Clean Water Act is required. That reversed an earlier ruling by another appeals court.

The Environmental Protection Agency has interpreted daily pollutant loads as seasonal or annual averages, particularly for agencies like WASA that operate combined sewer overflow collection systems.

NACWA General Counsel Alexandra Dunn says that because CSO systems' daily pollutants can vary greatly, limits probably would have to be raised well above current seasonal averages to accommodate the fluctuation, effectively rolling back overall protections.

WASA officials say the ruling would force it to redesign a $2.2- billion capital plan, hiking costs.