National Pollutant Discharge Elimination System (NPDES)

Watershed-based Permitting

Watershed-based permitting is a process that emphasizes addressing all stressors within a hydrologically defined drainage basin, rather than individual pollutant sources on a discharge-by-discharge basis. Watershed-based permitting can encompass a variety of activities ranging from synchronizing permits within a basin to developing water quality-based effluent limits using a multiple discharger modeling analysis.

The type of permitting activity will vary depending on the unique characteristics of the watershed and the sources of pollution affecting it. The ultimate goal of this effort is to develop and issue NPDES permits that optimally protect entire watersheds. EPA's Water Quality Trading Policy describes flexible approaches to meeting water quality requirements.

Background Information
- Watershed-Based NPDES Permitting Policy Statement Memorandum -- Describes the benefits of watershed-based permitting, the implementing mechanisms for this component of the watershed approach, and how EPA will be encouraging use of watershed-based NPDES permits.
- Watershed-Based NPDES Permitting: Rethinking Permitting As Usual -- A brochure that defines watershed-based NPDES permitting, as well as potential approaches and benefits. Also provides examples of watershed-based permitting happening around the country and EPA's efforts to promote this approach.
- Watershed-Based Permitting under the NPDES Program: A Summary of Related Background Information -- Provides a compilation and summary of background information relevant to watershed-based permitting.
- Potential Partners in Promoting Watershed-Based Permitting: An Analysis of Watershed Organizations -- Provides a cross-sectional analysis of successful organizations engaged in watershed management. EPA analyzed 29 selected organizations in 17 states for potential that these organizations may have to play a role in implementing watershed-based NPDES permitting based on their current goals and activities.
  - Appendix A
Guidance
- Watershed-Based National Pollutant Discharge Elimination System (NPDES) Permitting Implementation Guidance -- Describes EPA's recommended steps and ideas for watershed-based permitting implementation under the NPDES permit program. This approach, aimed at achieving new efficiencies and environmental results, provides a process for considering all stressors within a hydrologically defined drainage basin or other geographic area, rather than addressing individual pollutant sources on a discharge-by-discharge basis.
- Watershed-Based National Pollutant Discharge Elimination System (NPDES) Permitting Technical Guidance -- A follow up to the 2003 Watershed-based NPDES Permitting Implementation Guidance, it provides more detail concerning a number of permit development and issuance questions not addressed previously. It focuses on helping NPDES authorities develop and issue NPDES permits that fit into an overall watershed planning and management approach with input from watershed stakeholders.
Case Studies
To promote the innovative watershed-based permitting approach, EPA has generated a case study fact sheet series that presents an overview of watershed-based permitting efforts.