Setting the Stage: Background on Federal Stormwater Regulations

Congress passed the Clean Water Act in 1972 to address the growing public concern over the rising evidence of water quality and water resources degradation across the country. The Clean Water Act (CWA) sought to improve water quality in streams and rivers across the country by managing the level of pollutants emanating from point source discharges, such as outfalls from factories and wastewater treatment plants. By the end of the decade following the passage of the CWA, noticeable improvements in water quality were evident in many of the nation’s most impaired streams and rivers. Yet within that decade, there was a growing recognition that the management of point source discharges alone would not improve water quality to the extent needed to avoid impairment. It soon became clear that further action was needed to address non-point source pollution, including runoff from stormwater.

The regulations included in the CWA did not require stormwater discharges to be permitted unless they were contaminated by industrial waste or could be shown to be a significant contributor to water pollution. This decision was in part due to the expected heavy bureaucratic burden that would result from managing the nation’s vast stormwater infrastructure. But as development and new impervious surfaces continued to spread across the nation, the volume of stormwater runoff flowing into the nation’s water bodies increased. Local communities became gradually more aware of the runoff-driven impairments in their water ways. In 1987, Congressed (through the Water Quality Act) amended the CWA to require certain stormwater discharges to be regulated under a National Pollutant Discharge Elimination System (NPDES) permit.

 To reduce the administrative burden of overseeing this program, the EPA granted the authority to administer NPDES permits to the states. In Pennsylvania, the Department of Environmental Protection is responsible for administering the NPDES system. In 1990, Phase I of the NPDES stormwater program was established, which required municipalities with large (serving >250,000 residents) and medium (serving >100,000 residents) municipal separate storm sewer systems (MS4s) to reduce pollutants in stormwater to the “maximum extent practicable”. MS4s are defined as conveyances or systems of conveyances (i.e. systems designed to drain stormwater from roads or parking areas, ditches, or man-made channels) owned and operated by a public entity and not part of a combined sewer system or publicly-owned treatment works. In Pennsylvania, the Phase I regulations applied to the cities of Philadelphia and Pittsburgh.

With the continued sprawl of development and impervious surfaces away from city centers, regulators acknowledged that the management of stormwater runoff in urbanized areas beyond the bounds of medium and large MS4s was necessary. To address runoff in urban areas not covered under the Phase I rulings, the Stormwater Phase II Rules went into effect in 1999, which extended NPDES permit coverage to small MS4s (serving <100,000 residents). This required operators of small MS4s to reduce the discharge of pollutants to the “maximum extent practicable”, to protect water quality, and to satisfy the appropriate water quality requirements of the Clean Water Act. Any municipality with areas that are included in “urban areas”, as defined by the Bureau of the Census, are required to apply for an NPDES permit for their MS4 discharges. Municipalities may apply for a waiver from the program requirements if they can justify reason for exemption.

The Framework: Municipal Requirements under the MS4 Program:

Under the Phase II Rules, municipalities are required to implement a best management-based program to reduce the discharge of pollutants in stormwater. Best Management Practices (BMPs) generally fall into two categories: structural BMPs (including detention and infiltration basins, rain gardens, vegetated swales, and porous pavement) and non-structural BMPs (public education, street sweeping, and stormwater infrastructure inspection schedules). Permittees are required to develop a Stormwater Management Program (SWMP) Plan that outlines how they will meet the permit requirements. The SWMP Plan is required to include lists of specific BMPs and actions that are designed to satisfy the terms of their specific permits.

In Pennsylvania, all but Pittsburgh and Philadelphia are classified as small MS4s (less than 100,000 residents). Most small MS4’s are eligible to apply using a General Permit. Municipalities with discharges to streams designated as High Quality or Exceptional Value, outfalls that contain toxic or hazardous pollutants or that co-mingle with non-stormwater discharge, or that discharge to a stream with an assigned pollutant load are not eligible for a General Permit, and thus must apply for an Individual Permit.  To determine if your local streams are classified as Exceptional Value or High Quality, visit the Chester County Water Resources Authority’s (CCWRA) interactive map, and click on the “Protected Uses” tab.

PA DEP assesses streams throughout the state and classifies them as “impaired” or “attaining” based on whether they are meeting the water quality standards assigned to their designated uses. More information about DEP’s stream classifications can be found here. You can click on the “Impaired Waters” tab in this interactive map to see impaired streams in your municipality.

 If an MS4 includes outfalls to streams that have been assigned a specific pollutant loading, referred to as a Total Maximum Daily Load (TMDL), the SWMP must demonstrate how the BMPs implemented will help to meet the streams assigned loads by setting pollution reduction targets over the next five years. Even in the absence of a TMDL, Pennsylvania currently DEP requires applicants to develop such a Pollution Reduction Plan (PRP) if an MS4 discharges to a stream whose designated cause of impairment is nitrogen, phosphorus, or sediment. The purpose of this plan is to detail how the municipality will meet pollution reduction targets. Under future permit cycles, the DEP could require MS4s to develop PRPs for additional impairments beyond nitrogen, phosphorus, and sediment. To learn more about drafting a PRP, please see DEP’s Pollutant Reduction Plan Instructions document.

Implementing the Plan: The Minimum Control Measures

The Phase II Rules defined the current stormwater management framework (the non-structural BMPs) that consists of six components, known as “Minimum Control Measures” (MCMs). Each municipality must structure their stormwater management plan around these six measures. The six MCMs are:

  • Public Education and Outreach,
  • Public Participation/Involvement,
  • Illicit Discharge Detection and Elimination,
  • Construction Site Runoff Control,
  • Post-construction Runoff Control, and
  • Pollution Prevention/Good Housekeeping.

Proposed actions under each MCM can follow a set of BMPs that are recommended by DEP; applicants can also provide alternative BMP’s with measurable goals for any MCM. Applicants must maintain appropriate documentation of the completion of BMPs under each Minimum Control Measure and file an annual report detailing progress in implementing the SWMP plan. Documentation can include copies of educational materials, attendance lists to public outreach and education events, copies of presentations, and training and inspection records. Below is a brief summary of each of the six Minimum Control Measures and their respective lists of DEP-recommended BMPs. 

MCM #1: Public Education and Outreach­— The goal of this MCM is to provide residents with information about the impacts of stormwater runoff and the actions they can take to reduce their stormwater footprint. Under this MCM, municipalities must identify their target audience (typically local residents or visitors to municipal facilities) and develop a program designed to provide information about local stormwater impacts and management. This program includes distributing educational materials, such as pamphlets and flyers, and including stormwater information in local newsletters. DEP’s recommended BMP’s include:

  • BMP 1: Develop, implement, and maintain a Public Education and Outreach Program (PEOP).
  • BMP 2: Develop and maintain lists of target audience groups served by stormwater system.
  • BMP 3: At least once annually, publish one newsletter, pamphlet, flyer, or website that includes general stormwater information.
  • BMP 4: Distribute educational materials and information to target audiences identified in BMP 2 using at least two distribution methods.

MCM #2: Public Participation/Involvement— The goal of this MCM is to involve the public in stormwater activities and to facilitate completion of the SWMP Plan by gaining public support, connecting with local experts, and building partnerships. This MCM should complement the PEOP developed under MCM1.

  • BMP 1: Develop and implement a public involvement and participation program. This program should outline the programs that will be implemented to promote public input, outlines communication with partners in the MS4 area, and methods of making MS4 data available to the public
  • BMP 2: Provide adequate public notice and opportunities for the public to review and provide their input and feedback on any stormwater ordinances
  • BMP 3: Regularly solicit public involvement from members of the target audience. This meeting should review the implementation of the SWMP and should provide time for the target audience to provide input and feedback. A minimum of 1 meeting per year is required.

MCM #3: Illicit discharge detection and elimination (IDD&E)— The goal of the IDD&E program is to locate and stop illicit discharge into a municipality’s MS4 system. Illicit discharge can include the dumping of oil, septic overflow, and pool water into the components of an MS4 system.

  • BMP 1: Develop and implement a written IDD&E program for the detection, elimination, and prevention of illicit discharges into your MS4.
  • BMP 2: Map all streams and MS4 outfalls.
  • BMP 3: Map the storm sewer collection system including pipes, municipal watershed boundaries and roads.
  • BMP 4: The municipality must complete and document outfall screenings. New permittees must screen each outfall twice during their five year permit period. After the completion of the first five year permit cycle, outfalls must be screened once during each permit cycle.
  • BMP 5: Enact a stormwater management ordinance to implement and enforce a SWMP. This ordinance must meet the requirements listed in the MS4 Stormwater Management Ordinance Checklist. Chester County Act 167 Model Ordinance that was adopted by all County municipalities in 2013 and 2014 meets these requirements.
  • BMP 6: Provide education outreach on IDD&E to your target audience. This program should encourage and facilitate public reporting of illegal discharges.

MCM #4: Construction Site Runoff Control— This MCM helps municipalities protect waterways from stormwater-related pollution emanating from construction activities. When submitting your permit application for your MS4 permit, municipalities must decide whether they will use DEP’s Qualifying Local Program (QLP), or develop own program. In Pennsylvania, DEP’s Chapter 102 Program is the QLP. This program satisfies all MCM 4’s BMPs and BMPs 1-3 of MCM 5. In Chester County, the Conservation District administers this program.

  • BMP 1: Develop a written construction site stormwater runoff control program that includes permitting, inspections, and enforcement.
    • BMP 2: Write, adopt, and enforce an ordinance that requires implementation of erosion and sediment control BMPs and sanctions to ensure compliance.
    • BMP 3: Develop and implement requirements for site operators to control waste at the construction site that may cause adverse impacts
    • BMP 4: Develop and implement procedures for the receipt and consideration of public inquires, concerns, and information submitted by the public regarding local construction activities.

MCM #5: Post-Construction Stormwater Management— Freshly disturbed ground is highly susceptible to erosion during storm events and can deliver substantial loads of sediment to local waterways. The goal of MCM #5 is to avoid the increased stormwater runoff and increased sediment loads that often occur after construction. DEP’s recommended BMP’s are as follows:

  • BMP 1: Develop a post-construction stormwater management procedure that includes minimum requirements for the use of structural and non-structural BMPs for development and redevelopment, criteria for selecting and sizing stormwater BMPs, and implementation of an inspection program to ensure proper BMP installation.
  • BMP 2: Require the implementation of both structural and non-structural BMPs that minimize water quality impacts and maintain pre-development runoff conditions
  • BMP 3: Ensure that installed controls prevent and minimize water quality impacts.
  • BMP 4: Enact, implement, and enforce a post-construction runoff ordinance to address new development and redevelopment projects.
  • BMP 5: Develop and implement measures to encourage and expand the use of Low Impact Development in both new and redevelopment projects.
  • BMP 6: Ensure adequate operation and maintenance of all post construction stormwater management BMPs installed at all qualifying development and redevelopment projects.

MCM #6: Pollution Prevention/Good Housekeeping— Continued maintenance and regular inspection is needed to ensure stormwater facilities and impervious surfaces do not contribute additional runoff and sediment loads to local water ways. MCM #6 seeks to help ensure a reduction in the amount of pollution that originates on municipally-owned facilities (streets, parking lots, storm sewer systems).

  • BMP 1: Inventory all facilities and activities that are owned or operated by the permittee and have the potential for generating stormwater runoff, including roads, parks, and stormwater conveyance systems.
  • BMP 2: Develop, implement, and maintain a written operation and maintenance program for all municipal operations and facilities that could contribute to pollutant discharge regulated MS4s.
  • BMP 3: Develop and Implement and employee training program that addresses appropriate topics to further the goal of preventing or reducing pollution from municipal operations to your MS4.