In what can be deemed a victory for practical regulation, the U.S. Environmental Protection Agency (EPA) has withdrawn its rule that would have placed a stringent numeric limit on storm water flows from construction sites nationwide. 

In December 2009, EPA adopted a regulation placing a limit of 280 turbidity units on the sediment in storm water flows from construction sites 10 acres and larger—the first time the agency had ever adopted a numeric limit for construction storm water.  This numeric effluent limit was seen by many in the building industry as scientifically unjustified, potentially unachievable in certain instances, and extremely costly. 

The National Association of Home Builders (NAHB) and the Small Business Administration, among others, filed legal challenges to the numeric limit.  The challenges centered upon the flawed science that EPA used to support its rule as well as the extreme cost of implementation—claimed by NAHB to be up to $10 billion annually, a cost that could significantly hurt small businesses and affordable housing. 

On August 13, 2010, EPA filed papers with the 7th Circuit Court of Appeals asking the Court to vacate the numeric limit and place the lawsuit on hold while EPA proposes a revised rule.  EPA admitted that it had improperly interpreted the data underlying the numeric limit, and thus, would seek additional public comment and data and revise its rule in light of new comments, new data, and with proper interpretation of the data.    

While the numeric limit in EPA’s construction storm water regulations would be placed on hold, other non-numeric aspects of EPA’s rules will remain in effect—regulations specifying minimum best management practices and other similar requirements. 

In California, a lawsuit filed by the California Building Industry Association is challenging a similar type of numeric storm water effluent limit.  That limit is contained in the statewide general construction storm water permit adopted in September 2009 by the State Water Resources Control Board.  Although the two numeric limits are different (280 turbidity units for all sites 10 acres or larger for EPA and 500 turbidity units for all “risk three” sites in California), EPA’s decision to go back to the drawing board on its numeric limit could have an effect on the lawsuit pending in California.  Briefs have not yet been filed in the California case.