Southeastern Pa. Groundwater Protected Area (SEPA-GWPA)
Creation and Description of the SEPA-GWPA

The Southeastern Pennsylvania Ground Water Protected Area (SEPA-GWPA), where more stringent regulations apply to ground water withdrawals than they do in the rest of the Delaware River Basin, was initially established by DRBC Resolution No. 1980-18 (pdf 2.1 MB) at the request of the Commonwealth of Pennsylvania after it became evident that development was negatively impacting ground water levels in the Triassic lowland and adjacent area of southeastern Pennsylvania.

This resolution created the requirement that new or expanded well water projects located within the delineated GWPA involving an average withdrawal of more than 10,000 gallons per day (gpd) from a well or group of wells operated as a system must obtain a DRBC Protected Area Permit. In the remainder of the Delaware River Basin, DRBC's review threshold for water withdrawal projects is for an average withdrawal of more than 100,000 gpd during any calendar month.

The main goal of the GWPA is to prevent the depletion of ground water. Lowered water tables in the GWPA have reduced flows in some streams and dried up others. This reduction in baseflows affects downstream water uses, negatively impacts aquatic life, and can reduce the capacity of waterways in the region to assimilate pollutants.

Another goal is to protect the interests and rights of lawful users of the same water source, as well as balance and reconcile alternative and conflicting uses of limited water resources in the region.

Between 1990-2013 total withdrawals were reduced by approximately 8.5 billion gallons, or 23.4 million gallons a day; more surface water from various sources, including the Delaware River, is being used for water supply.


Listing of Counties and Municipalities Included in the GWPA

Approximately one million residents of southeastern Pennsylvania currently rely entirely or substantially on the ground water resources underlying Berks, Bucks, Chester, Lehigh, and Montgomery counties for supplies of domestic, municipal, commercial, industrial, and agricultural water.

The GWPA takes in 1,200 square miles and includes 127 municipalities. In addition to the Neshaminy Creek Watershed, other large drainage areas include the Brandywine Creek, Perkiomen Creek, and Wissahickon Creek subbasins.

In addition to all of Montgomery County, the following areas in surrounding counties fall within the Protected Area:

Berks: the townships of Douglass, Hereford, and Union.

Bucks: the townships of Bedminster, Buckingham, Doylestown, East Rockhill, Hilltown, Lower Southampton, Middletown, Milford, New Britain, Newtown, Northampton, Plumstead, Richland, Upper Southampton, Warminster, Warrington, Warwick, West Rockhill, and Wrightstown; the boroughs of Chalfont, Doylestown, Dublin, Hulmeville, Ivyland, Langhorne, Langhorne Manor, New Britain, Newtown, Penndel, Perkasie, Quakertown, Richlandtown, Sellersville, Silverdale, Telford, and Trumbauersville.

Chester: the townships of Birmingham, Charlestown, East Bradford, East Coventry, East Goshen, East Pikeland, Easttown, East Vincent, East Whiteland, North Coventry, Schuylkill, South Coventry, Thornbury, Tredyffrin, Warwick, West Bradford, West Goshen, Westtown, Willistown, and West Whiteland; the boroughs of Elverson, Malvern, Phoenixville, Spring City and West Chester.

Lehigh: Lower Milford Township.

Click the 'Map of Counties and Municipalities within the GWPA' link on the right to view a map of the area. 

Percent of Groundwater Use in the Delaware River Basin: 1997-2017


This time series video shows the percent of groundwater use in the Delaware River Basin as compared to the available groundwater per hydrologic unit (watershed ID #) for the years 1997 - 2017. The Southeastern PA Groundwater Protected Area and NJ's Critical Area 2 are delineated; these are known areas of groundwater stress in the basin. The time series was created by DRBC staff using data from the USGS.