Final EPA Rule for Storm Water Runoff at Construction Sites Is Issued

Last week, the U.S. Environmental Protection Agency ("EPA") issued the final rule regarding storm water runoff from construction sites. The long debated and awaited final rule takes effect in February 2010 and will be phased in over a four year period.

The rule requires construction site owners and operators to implement a variety of erosion and sediment control best management practices. The rule also requires construction site owners and operators who impact 10 or more acres to monitor storm water discharges and comply with a numeric standard for the pollutant turbidity in those discharges. While best practice measures aimed at erosion and sediment control are part of current storm water regulations, the national requirement to monitor discharges to ensure they comply with enforceable numeric limits is novel in the regulation of construction site storm water.

The size of a construction site will determine whether – and when – owners and operators will be required to monitor discharges and comply with numeric limits. Construction sites that disturb 10 or more acres at one time will be subject to such requirements, and such requirements will begin four years after the effective date of the rule. Construction sites that disturb 20 or more acres at one time will be required to comply with the monitoring and numeric limits beginning 18 months after the effective date of the final rule. Construction sites that disturb less than 10 acres at one time will not be subject to the monitoring and numeric limit requirements. Construction site owners and operators that disturb one or more acres need only use best management practices to ensure that soil disturbed during construction activity does not pollute nearby water bodies.