As a result of petitions from NAHB and the Small Business Administration, the U.S. Environmental Protection Agency has finally acted to strike an onerous requirement from new national storm water management regulations.

On Nov. 3, the EPA issued a direct final rule to remove the numeric limitation of 280 NTUs (numeric turbidity units) from its new Construction and Development Effluent Limitation Guidelines (ELGs).

In setting the limit for the NTUs — which are a measure of water cloudiness — the agency failed to take into account the natural turbidity of streams and lakes throughout the country. In some cases, these have higher levels of NTUs then water discharged from construction sites.

The EPA concluded that “it improperly interpreted the data and, as a result the calculations in the existing administrative record are no longer adequate to support the 280-NTU numeric limit.”

In its petition, NAHB pointed out that there were technical errors in the data used to develop the ELG, including a misinterpretation of vendor-supplied figures on storm water control devices.

In addition, the EPA set the limit using data from advanced instead of passive treatment systems. Excluding the advanced systems from consideration would have put the standard in the neighborhood of 800 NTUs.

States in the process of adding the 280-NTU limit to their permits will have to issue their permits without the numeric limit.

Next month, the EPA plans to submit for public comment a proposed rulemaking to correct the numeric effluent limitation of 280 NTUs.

It also is planning to issue a final rule with a new numeric effluent limit by May 30, 2011. A fact sheet and the federal register notice are available on the EPA website.

Meanwhile, the other provisions of the ELG rule remain valid and will require builders and developers to follow best management practices relating to erosion and sediment control, soil stabilization, dewatering, pollution prevention and prohibited discharges. 

These requirements are in many cases more stringent than builders and developers have been used to, and NAHB is seeking guidance from the EPA on how states and industry should implement these provisions.

Affecting Idaho, Massachusetts, New Hampshire, New Mexico and the District of Columbia — which have not yet been authorized to administer the National Pollutant Discharge Elimination System (NPDES) permit program — the EPA will include the ELG requirements in its Construction General Permit when it is reauthorized in July 2011.

The remaining states must each incorporate the non-numeric sections of the ELG the next time they issue a new construction general permit.

For more information, e-mail Ty Asfaw at NAHB, or call her at 800-368-5242 x8124.

Are You Ready for a Visit From the EPA? 

“Storm Water Permitting: A Guide for Builders and Developers,” available through BuilderBooks.com, provides a starting point for builders and developers to use in locating and understanding storm water permitting requirements.

The publication has been prepared to help builders comply with the U.S. Environmental Protection Agency's stormwater requirements, and includes information on state permitting programs and more than 50 of the most commonly used Best Management Practices.

Also included are tips on compliance, including how to handle visits from inspectors.

To view or purchase this guide online, click here, or call 800-223-2665.