On December 1, 2009, the United States Environmental Protection Agency (“EPA”) published a Final Rule (“Rule”)[1] that will have a sweeping impact on the construction industry. For the first time, EPA will impose monitoring requirements and enforceable numeric limitations on construction site stormwater discharges. The Rule subjects construction site owners and operators to a broad range of erosion and sediment control measures and pollution prevention practices designed to control discharges from construction site activities, including grading, clearing and excavation. The EPA’s goal is to reduce the approximately four billion pounds of sediment and other materials discharged from construction sites using the best practicable control technology (“BPT”) currently available. The EPA estimates that the Rule will be applicable to more than 82,000 construction sites and will result in approximately $1 billion in annual compliance costs.

The Rule has a four-year phase-in period. Commencing on February 1, 2010, owners and operators of all sites larger than one acre will be required to use best management practices (“BMPs”) to ensure that soil disturbed during construction does not pollute water bodies located in proximity to each site. Beginning in August 2011, owners and operators of sites larger than 20 acres must conduct site discharge monitoring and comply with numeric effluent limitations. After February of 2014, these new requirements will become applicable to owners and operators of sites larger than 10 acres. Although the Rule is initially limited to the District of Columbia, four states, and other jurisdictions in which the EPA issues construction permits (several U.S. territories and tribal areas), states that issue their own construction permits must incorporate the requirements of the Rule into any new general permits issued after February 2010.

Erosion and Sediment Controls, Soil Stabilization and Dewatering

All site owners/operators subject to the Rule will be required to design, install and maintain effective erosion and sediment controls designed to minimize the discharge of pollutants. These efforts must control stormwater volume and velocity to minimize soil, downstream channel and streambank erosion, minimize the amount of soil exposure and compaction during construction activity, preserve topsoil and minimize disturbance of steep slopes. Site owners and operators must also minimize sediment discharges, provide and maintain natural buffers around surface waters, direct stormwater to vegetated areas and maximize the infiltration of stormwater. Construction site owners must also immediately initiate soil stabilization of disturbed areas when clearing, grading excavation and other earth disturbing activities have ceased for a period of 14 days or more.

Pollution Prevention Measures

Site owners/operators must design, install and maintain measures that will minimize the discharge of pollutants from equipment and vehicle washing, including a prohibition on the discharge of soaps and solvents used in washing. The Rule also requires owners/operators to minimize exposing building materials, construction wastes, fertilizers, pesticides and other materials to rain and stormwater and to implement spill and leak prevention and response procedures. The Rule also prohibits discharges of fuels and oils from vehicles and other equipment and from wastewater from washout and/or cleanout of concrete (unless managed by appropriate controls), stucco, paint, curing compounds and other construction materials.

Numeric Turbidity Limitations for Large Sites

The Rule also represents EPA’s initial imposition of testing requirements for daily maximum turbidity limits (particles suspended in liquids) on discharges from construction sites. Owner/operators of sites larger than 20 acres must comply with these testing requirements (and corresponding turbidity limits) after August 2011. Likewise, these requirements become applicable to sites larger than 10 acres after February 2014. The daily average cannot exceed 280 NTU (nephelometric turbidity units - the standard testing unit used to determine the amount of particulates in water samples), except for those days that rainfall exceeds a 2 year, 24-hour storm event. The turbidity limit in the Rule is a substantial relaxation from the 13 NTU limit proposed in the draft rule, although EPA expanded its scope significantly by reducing the minimum size of regulated sites from 30 to 10 acres.