Phase II MS4 Program Requirements

The Phase II rule will require the development of programs in support of six minimum control measures. Each Regulated Small MS4 will be required to develop a Stormwater Management plan that incorporates all of the six minimum control measures. Read the following six minimum control measures.

Public Education and Outreach

The EPA recommends this control be focused on three areas.

  • Encourage MS4s to form partnerships with other governmental and non-governmental entities to establish more cost-effective regional or statewide programs.
  • Educational material and strategies should be relevant to local issues. Existing materials from governmental, public interest, or trade organizations may be used for this purpose.
  • The education program should be applicable and available to all communities, including industrial and commercial entities that may likely have considerable stormwater impacts.

Public Participation and Involvement

The involvement and participation of the public in the stormwater management program broadens public support and provides economic and intellectual resources otherwise unavailable. The purpose of public involvement and participation is to involve a diverse group of participants incorporating various ideas and concerns.

Illicit Discharge Detection and Elimination

Illicit discharges can contribute significant levels of pollutants to the storm sewer system. Untreated discharges containing heavy metals, oil and grease, bacteria, viruses, toxic materials, and other constituents can bear serious consequences on receiving waters, wildlife, and human health. The purpose of this control is to eliminate discharges to the stormwater system.

Construction Site Stormwater Runoff Control

Construction sites can contribute a considerable amount of pollutants to stormwater without appropriate runoff control measures. Sediment runoff is generally the primary concern. Short-term sediment runoff from a construction site can be equivalent to decades of sediment runoff in natural conditions. In addition, other pollutants such as oil and grease, pesticides, construction chemicals, construction debris, and various other construction-related pollutants, can contribute detrimentally to the physical, chemical, and biological conditions of aquatic habitats. This control requires the implementation of a program to reduce impacts on stormwater from construction activities.

Permanent (Post-Construction) Stormwater Management in New Development & Redevelopment

The intent of post-construction runoff control is to address two major impacts associated with new development or redevelopment. The first issue is the increased quantity of stormwater runoff due to a greater impervious area. The impervious areas prevent the percolation of water through soil and vegetation, increasing the volume channeled to the storm sewer system and producing higher and faster peak flows. The second major impact is an increase in the type and quantity of pollutants in stormwater runoff. Pollutants such as oil and grease, nutrients, chemicals, heavy metals, and pesticides often become suspended in runoff and are carried to receiving waters such as creeks, rivers, and lakes. The Phase II rule; therefore, requires the implementation and enforcement of a program to reduce these impacts.

Pollution Prevention/Good Housekeeping

The purpose of this control is to address potential water quality issues associated with municipal operations such as fleet management, materials storage, or operations such as landfill management or wastewater treatment.