SPC Water Resource Center SPC
Pennsylvania Stormwater Regulations

Did you know? SPC is providing FREE MS4 workshops to assist municipalities with MS4 compliance. Learn more here.

The federal Clean Water Act (CWA) prohibits the discharge of pollutants into waterways without the appropriate permits. Pennsylvania’s Stormwater Management Act (better known as Act 167), MS4 Program, Chapter 102 (Erosion and Sediment Control Requirements), and NPDES Permit Program for Stormwater Discharges Associated with Construction Activities are amongst the Commonwealth’s methods for meeting the runoff-related requirements of the Clean Water Act. ‚Äď taken from http://www.stormwaterpa.org/how-to-apply-best-practices.html.

What Is An MS4?

An MS4 is a conveyance or system of conveyances that is:

  • Not part of a publicly owned treatment works (sewage treatment plant)
  • Owned by a state, city, town, village, or other public entity that discharges to waters of the U.S.;
  • Designed or used to collect or convey stormwater (including storm drains, pipes, ditches, etc.); and
  • Not a combined sewer.

MS4

Public education and outreach is one of the Minimum Control Measures (MCMs) required for compliance with MS4 permits.
Public education and outreach is one of the Minimum Control Measures (MCMs) required for compliance with MS4 permits.

The stormwater requirements of the federal Clean Water Act are administered under the Pennsylvania Department of Environmental Protection’s Municipal Separate Storm Sewer (MS4) Program.¬†

Stormwater runoff in urban areas is transported either through Municipal Separate Storm Sewer Systems (M4s) or, in a Combined Sewer System (CSS). An MS4 is designed to carry only wastewater to the treatment plant, and stormwater is carried in a separate system. In a CSS, which is typical of older cities, both wastewater and stormwater are carried in the same pipes, which may overflow during periods of heavy rain or snow melt. To prevent harmful pollutants from being washed or dumped into an MS4, operators must obtain a NPDES permit and develop a stormwater management program.

  • Phase I, issued in 1990, requires medium and large cities or certain counties with populations of 100,000 or more to obtain NPDES permit coverage for their stormwater discharges. There are approximately 750 Phase I MS4s.
  • Phase II, issued in 1999, requires regulated small MS4s in urbanized areas, as well as small MS4s outside the urbanized areas that are designated by the permitting authority, to obtain NPDES permit coverage for their stormwater discharges. There are approximately 6,700 Phase II MS4s.

Generally, Phase I MS4s are covered by individual permits and Phase II MS4s are covered by a general permit. Each regulated MS4 is required to develop and implement a stormwater management program (SWMP) to reduce the contamination of stormwater runoff and prohibit illicit discharges.

Learn more about how it’s applied in Pennsylvania at Stormwater PA.

More Information

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 Policy & Regulations

 

Who We Are

Staff
Erin Kepple Adams
Marti Battistone

Pennsylvania Stormwater Regulations

State & Federal Water Laws
Federal Laws | Pennsylvania Code

Regulatory Agencies & Legislative Resources

 

Watershed Information and Regional Watershed Conservation Plans

GIS Data Sources

Green Infrastructure

 

Regional Stakeholders

Key Contacts

Tools

Grants & Funding Resources

Land Use/Land Cover
Allegheny | Armstrong | Beaver |
Bulter | Fayette | Greene | Indiana |
Lawrence | Washington |
Westmoreland

 

Water Resource Maps
MS4 Communities in the SPC Region
Act 167 Watersheds

Impaired Waterways by Source
Designated Uses in SPC Region
Total Maximum Daily Loads (TMDLs) for Impaired Waterways
Population Density
Bedrock Formations

 

Municipal Separate Stormwater System (MS4)

SPC Educational Resources

SPC Workshop Materials

Glossary

Stormwater Management & Best Management Practices

Free Educational Webinars and Online Training

Resources for Student Education

 

SWPA's Homeowner's Guide To Stormwater

Climate Change and Water Resources

Resources for Water Suppliers & Wastewater Managers

Additional Water
Quality Information

NEW! Quick Resource Guide to the MS4 Program

NEW! Quick Resource Guide for Winter Maintenance BMPs

Allegheny County   Phase 1 of Act 167 work for Allegheny County is currently being finalized (as of 12/2013)
Armstrong County  

Act 167 work was completed for Glade Run Watershed in 1991.  View the document here.

Beaver County  

Beaver County has completed Phase 1 of the Act 167 planning process.  View the document here.

Butler County  

Butler County has completed the entire Act 167 planning process.  View the finalized Phase 1 and Phase 2 documents as well as the model ordinance:

Phase 1 | Phase 2
Model Ordinance

Fayette County  

Fayette County has completed the entire Act 167 planning process.  View the finalized Phase 2 document (model ordinance included in Appendix B) here.

Greene County  

The Act 167 Planning Process has not yet been completed in Greene County.

Indiana County  

The Act 167 Planning Process has not yet been completed in Indiana County.

 

Lawrence County  

Lawrence County has completed the entire Act 167 planning process.  View the finalized Phase 1 and Phase 2 documents as well as the model ordinance:

Phase 1 [ phase 1 maps ] | Phase 2
| Model Ordinance |

Allegheny County  

Washington County has completed the entire Act 167 planning process.  View the finalized Phase 2 documents and model ordinance documents below: 

Phase 2

Plate 1: Base Map | Plate 2: Land Use
Plate 3: Future Growth | Plate 4: Soils
Plate 5: DEM | Plate 6: Geology
Plate 7: Problems | Plate 8: Flood Control
Plate 9: Floodplain | Plate 10: SWM Districts

 

Westmoreland County  

Westmoreland County has completed Phase 1 of the Act 167 planning process.  View the document here.