New Federal Storm Water Permitting Requirements for Construction Sites and Small Municipalities
 
March 1, 2000
 

Under long-awaited new EPA storm water regulations that became effective February 7, 2000, construction sites that are as small as one acre in size, and possibly even smaller, will now be covered under the federal Clean Water Act's National Pollutant Discharge Elimination System (NPDES) permit program. The new regulations, known as "Phase II" of EPA's storm water program, require storm water discharges from construction site activities, including clearing, grading, and excavating land that disturb between one and five acres in size, to be covered under the NPDES program (construction site activities disturbing over five acres are regulated under Phase I of the program). Such activities that disturb less than one acre of land may also be covered under the NPDES program if they are part of a larger common plan of development or sale with a planned disturbance of one to five acres or if a project is deemed by the relevant permitting authority (either the EPA or a state that has been delegated to implement the NPDES program) to have the potential for adverse impacts on water quality. The Phase II regulations allow a permitting authority to grant waivers where little or no rainfall is expected during the period of construction or where, based on water quality and watershed considerations, storm water discharge controls are not needed.

Under the Phase II regulations, operators of construction sites that will disturb between one and five acres of land must submit NPDES permit applications at least 90 days before the date on which construction is to commence. However, discharges from such sites will not be subject to the Phase II regulations until March 10, 2003, unless designated for coverage before then by the permitting authority. Permitting authorities will be developing programs and regulations to implement these new requirements over the course of the next year.

Phase II also expands the NPDES permitting program to cover discharges from small municipal separate storm sewer systems, known as "MS4s," located in "urbanized areas" (the Phase I rules addressed larger MS4s). An "urbanized area" is defined as a city or town and its adjacent densely populated surrounding area that together have a minimum population of 50,000. EPA or a state permitting authority may require additional small MS4s to comply with the Phase II regulations after developing criteria for identifying these otherwise unregulated MS4s. According to the Phase II regulations, operators of small MS4s must develop and implement storm water management programs designed to reduce their discharges of pollutants to the "maximum extent practicable" (MEP) and to protect water quality. Such programs must include the following minimum control measures: (1) public education and outreach; (2) public involvement and participation; (3) illicit discharge detection and elimination; (4) construction site storm water runoff control; (5) post-construction storm water management; and (6) pollution prevention, or "good housekeeping," for municipal operations.

The Phase II regulations require that each MS4 include in its NPDES permit application appropriate "best management practices" (BMPs) to satisfy the above-listed measures, as well as measurable goals for each control measure. By November 2000, EPA must issue a menu of BMPs for small MS4s and by November 2001, EPA must issue guidance on the development of measurable goals for MS4s.

The Phase II regulations also provide an opportunity for all "storm water discharges associated with industrial activity" to be excused from permitting requirements by certifying that storm water will not be exposed to contaminants. A certification form is included in the Phase II regulations, and a demonstration must be made to justify such certification.

EPA's Phase II regulations represent a significant expansion of EPA's efforts to control polluted storm water runoff. Operators of small construction sites and small MS4s should be aware of these new requirements and consider participating, where possible, in the development of implementing programs and the establishment of BMPs in their areas.