In the latest turn of the ongoing saga of storm water regulation, the U.S. EPA has withdrawn its proposed rule that would have revised the enforceable numeric effluent limits for runoff from construction sites.  The numeric limits were established for turbidity in effluent limitation guidelines (“ELG”) adopted by EPA in December, 2009.  Once established for specific industrial sectors, ELGs must be incorporated in NPDES permits issued to point-source dischargers. 

This regulatory matter has been an arduous journey for EPA, one that may not reach a conclusion any time soon.  Following a lawsuit filed in 1989 by the Natural Resources Defense Counsel alleging that EPA had failed to meet its statutory obligation relative to discharges from construction and development, EPA identified that sector as an industrial point source category for further rulemaking under Clean Water Act section 304(m).  EPA then solicited comments in 2002 on a range of options to address construction storm runoff.  In 2004, EPA decided not to promulgate ELGs, drawing further litigation from NRDC, which did not end favorably for EPA.  A California District Court held in 2006 that once EPA lists an industrial point source category under section 304(m), it has a mandatory duty to promulgate ELGs and New Source Performance Standards (NSPS).  Meeting the court’s deadlines, EPA proposed ELGs and NSPS in November, 2008, and adopted them in December, 2009.  Construction storm water permits adopted after February 1, 2009 were required to incorporate the numeric effluent limits contained in the ELG. 

In November, 2010, EPA stayed the numeric turbidity limit in order to review its calculations used to set the limit. As a result, it had to extend the expiration date of the 2008 permit from June 20, 2011 to February 15, 2012 in order to allow time to incorporate the new numeric limitations in the new construction permit.  Most recently, on August 12, 2011, EPA withdrew its proposal in order to gather more data, a move that will extend the period of uncertainty for those subject to the federal construction storm water permit.

EPA’s 2009 ELG set a turbidity limit of 280 nephelometric turbidity units (NTU) for construction runoff.  As it turns out, California’s new Construction General Permit (“CGP”), adopted shortly before EPA adopted its ELG, set a numeric turbidity limit of 250 NTU.  The CGP timing conveniently relieved the State Water Resources Control Board of using EPA’s numeric limit until the following permit cycle.  While it may have been EPA’s proposed 13 NTU limit that propelled the state to adopt the CGP before EPA adopted the ELG, the good news is that California’s CGP is not subject to EPA’s continually shifting rulemaking.