Rules and Regulations

Storm Water Pollution Prevention

In 1987, Congress directed EPA to institute a national storm water management program in two phases. Phase I, which became effective in 1990, required National Pollution Discharge Elimination System (“NPDES”) permits for storm water runoff, discharged to certain municipal separate storm sewer systems (“MS4s”) or waters of the United States, associated with eleven categories of industrial activity, including construction sites disturbing five or more acres of land.

Phase II of EPA’s storm water regulations expands storm water permitting requirements to include construction activities disturbing one or more acres, but it also provides industries with a new certification process that may be used in lieu of permitting, provided they can demonstrate that all industrial materials are protected against storm water exposure.

The new rule also authorizes EPA to require permits for other storm water sources as necessary to implement total maximum daily load (“TMDL”) allocations, or to protect or achieve other water quality criteria. Businesses engaged in industrial or construction activities should be familiar with the Phase II rules and understand the options for complying with NPDES requirements in their jurisdictions.

Construction Activities

The Phase I storm water rules covered construction activities only if they disturbed, or were part of a “larger common plan of development or sale” that disturbed five or more acres of land. Where EPA is the permitting agency, developers usually can comply with this requirement by developing and implementing an appropriate Storm Water Pollution Prevention Plan, and submitting a Notice of Intent (“NOI”) to be covered by an applicable general permit at least two days prior to commencing their construction activities. Many states also have developed general permits covering “large” construction activity.

Under the Phase II rules, storm water discharges associated with “large” construction activities still require a NPDES permit. But the Phase II rules also require permits for storm water discharges associated with “small” construction activities, i.e., activities that disturb, or are part of a larger common plan that disturbs, a land area of equal to or greater than one and less than five acres.

In addition, the Phase II rules require a permit for construction activity disturbing less than one acre if the activity has been designated as potentially having serious adverse impacts on water quality. However, permitting authorities may waive NPDES permitting requirements for “small” construction site operators who are able to certify that their project is in an area where runoff is not expected to impact local water quality. Where permit requirements are not waived, operators may seek coverage under a general permit, as these become available.

Construction site operators also should be aware that operators of regulated MS4s are required to develop and implement programs to reduce pollutant runoff from construction sites. Local requirements, including site plan review and implementation of “best management practices,” may be more stringent than the conditions of an applicable general permit.

Other Industrial Activities

Under the Phase II rules, industrial facilities must continue to comply with NPDES storm water requirements through an individual permit, the Multi-Sector General Permit for storm water discharges, or another applicable general permit. However, the Phase II rules expand the availability of the “no exposure” exclusion, which previously was available only to operators of certain “light industrial” facilities. A conditional “no exposure” exclusion now is available to operators of all categories of regulated industrial activity (except construction activity) who can certify that their industrial materials and processes are adequately sheltered from rain, snow, snowmelt and runoff. Notably, any facility that previously relied on the automatic exclusion for “light industry” now must submit a certification of “no exposure” to qualify for the permit exemption. Industrial dischargers who previously qualified, and all dischargers who now may be eligible, should review their materials and waste handling practices to confirm that they qualify for the new exemption. They also should consider whether they need to update their Storm Water Pollution Prevention Plans and/or submit new NOIs for storm water discharged from secondary containment systems installed to comply with new requirements for regulated petroleum or chemical storage tanks.

Total Maximum Daily Loads (“TMDLs”)

A TMDL quantifies the maximum allowable loading of a pollutant to a designated water body, and allocates that wasteload to contributing sources in order to achieve or prevent a violation of water quality criteria. Under the Phase II rules, the permitting authority may require an NPDES permit for a storm water discharge based on TMDLs that address the pollutants of concern. As states continue to adopt and implement TMDLs, otherwise unregulated storm water discharges may be designated as requiring a permit on a case-by-case basis.

Additional Resources