EPA Publishes New Limits on Stormwater Discharge

February 2010Newsletters In the Zone

On December 1, 2009, the EPA published Effluent Limitation Guidelines , its first-ever numeric limit on stormwater discharges from construction sites. The agency believes this rule, which takes effect in February 2010 and will be phased in over four years, will significantly improve the quality of water nationwide.

Beginning on August 1, 2011, all sites that disturb 20 or more acres of land at one time are required to comply with a new turbidity limitation of 280 NTU (nephelometric turbidity units). On February 2, 2014, the limitation applies to all construction sites disturbing 10 or more acres of land at one time.

As part of the conditions of a constructionrelated NPDES permit, permittees will be required to sample, monitor and report turbidity levels as well as ensure that runoff from construction sites complies with the numeric limitation for turbidity. Runoff resulting from storm events exceeding the two-year, 24-hour storm is exempt.

The EPA's original proposal was to limit discharges to only 13 NTU—quite more restrictive than the final rule of 280 NTU. However, even at 280 NTU, developers will bear significant new construction costs. The rule changes were in response to a court order (Natural Resources Defense Council v.U.S. Environmental Protection Agency, 542 F.3d 1235 (9th Cir. 2008)) that compelled the EPA to make changes by December 1, 2009.

More information is available on the EPA web site.

For more information, please contact Robert W. Gundlach, Jr. at 215.918.3636 or [email protected].