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Pollutant Reduction Plan Instructions (PDF)

TMDL Plan Instructions (PDF)

To assist MS4s with understanding their obligations regarding impaired waters, DEP has prepared an MS4 Requirements Table. The Table consists of two parts – one for Municipal MS4s (PDF) and one for Non-Municipal MS4s (PDF). See also the MS4 Requirements Table Instructions (PDF) for understanding and using the Table and for methods to provide comments.

DEP has developed a supplement to the MS4 Requirements Table which is titled Pollutant Aggregation Suggestions for MS4 Requirements Table (PDF) (the Aggregation Table). The Aggregation Table helps permittees interpret the content of the MS4 Requirements Table by grouping the impaired surface waters into separate watersheds. See the Pollutant Aggregation Suggestions for MS4 Requirements Table Instructions (PDF) and FAQ for further explanation.

DEP has also developed a web-based GIS application that provides an improved visual representation of the information contained in the MS4 Requirements Table and the Aggregation Table.


Web-based training is available on the Clean Water Academy website.

Pollutant Reduction Plan Mapping Basics: This training was developed by DEP to assist MS4 permittees with developing mapping for their Pollutant Reduction Plans.

Stream Restoration Crediting: This training provides an overview of the documentation that DEP expects to see when stream restoration projects are submitted for review.


PRP Development Process Summary (PDF): This is a one-page step-by-step suggested approach for developing Pollutant Reduction Plans

Simplified Method Narrative (Word):
This paper describes methods that can be used to calculate existing pollutant load and the load reductions from BMPs.

Considerations of Stream Restoration Projects (PDF): This is a short description of the project siting and technique criteria that must be met in order for a stream restoration project to be eligible for MS4 pollutant load reduction credit.

Stream Restoration Crediting Checklists: Eligibility and Crediting Review Checklists have been developed to streamline the review process for stream restoration projects. Permittees are encouraged to review these checklists and become familiar with the level of documentation that DEP expects to see when stream restoration projects are submitted for crediting review.

DEP's Recommendations for Considering, Selecting and Financing Cost-Effective Stormwater Best Management Practices (BMPs) to Achieve Pollutant Load Reductions (PDF) offers suggestions on how to get started with developing PRP/TMDL Plans.

EPA TMDL website

DEP tool for looking up TMDLs in PA watersheds by different parameters

DEP Pennsylvania Stormwater Best Management Practices Manual


EPA National Stormwater Calculator
This calculator may be used to compute small site hydrology for any location within the US by estimating the amount of stormwater runoff generated from a site under different development and control scenarios over a long-term period of historical rainfall.

EPA Stormwater Management Model
A dynamic rainfall-runoff simulation model used for single event or long-term (continuous) simulation of runoff quantity and quality from primarily urban areas.

Planning Tools

Statewide MS4 Land Cover Estimates (PDF)
This document contains percent impervious and pervious cover, both inside and outside of urbanized areas, for each municipality with an MS4 in PA, which may be used to develop pollutant loading estimates for Pollutant Reduction Plans and TMDL Plans.

PA Urbanized Area Population Table (PDF)

Expert Panel Reports

Final CBP Approved Expert Panel Report on Stormwater Performance Standards (Long Version) (PDF)

Final CBP Approved Expert Panel Report on Stormwater Retrofits (Long Version) (PDF)

Stream Restoration Expert Panel Reports

Recommendations of the Expert Panel to Define Removal Rates for Street and Storm Drain Cleaning Practices (Long Version) (PDF)