Illinois Pollution Control Board Adopts First Time-Limited Water Quality Standard

On November 4, 2021, the Illinois Pollution Control Board approved a groundbreaking time-limited water quality standard (TLWQS) for chloride, applicable to the Chicago Area Waterway System and the Lower Des Plaines River, pending USEPA approval. The 15-year TLWQS allows a temporary variance from existing chloride standards while requiring dischargers to implement best management practices, develop individual pollution minimization programs, participate in a chloride workgroup, and submit annual progress reports. The ruling also establishes interim chloride criteria, enhanced monitoring requirements, and a permitting framework to ensure enforceability through NPDES permits, with mandatory re-evaluations after five and ten years.