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Ridge Run PFAS Site

Site Facts

Municipality/County: East and West Rockhill Townships, Bucks County
HSCA Site Since: 2016
Primary Contaminants of Concern:perfluorooctanoic acid (PFOA) & perfluorooctane sulfonate (PFOS)

What's New (As of April 2019)

Please refer to the Source Investigation and the Interim Response Action sections for updated information and documentation

Introduction/Site Discovery

  • Pursuant to its authority under the Hazardous Sites Cleanup Act of 1988 (HSCA), DEP is investigating groundwater in the area. The purpose of the investigation is to determine the extent of PFOA and PFOS in the aquifer underlying the area, which we are referring to as the Ridge Run PFAS HSCA Site.
  • After one public supply well in the area was found to contain combined concentrations of PFOA and PFOS that exceeded EPA's 70 ppt Health Advisory Limit (HAL), and another public supply well was found to contain combined concentrations slightly below the HAL, DEP immediately took steps to begin a thorough investigation of the surrounding area.

Private Drinking Water Investigation

  • Since November 2016, DEP has collected samples from more than 170 private wells within the area of interest surrounding the original contaminated public supply wells.
  • Results of this sampling ranged from non-detect (ND) to 16,360 ppt combined for PFOA/PFOS.
  • There are currently 13 properties which have had results above the HAL and are either equipped with effective carbon filtration systems or are receiving bottled water.
  • There are 2 properties which have had results above 40 ppt that are being monitored for any fluctuation above the HAL.

Source Investigation

In March 2019 - DEP conducted soil and surface water sampling at the Site. DEP plans to utilize the results of the sampling to help determine the best locations for the planned monitoring wells.. The monitoring wells will help DEP determine the vertical and horizontal extent of the groundwater contamination and the direction of groundwater flow in the area.

Press Releases/Public Notification

June 2, 2018: PA Bulletin Notice of Proposed Interim Response Ridge Run PFAS HSCA Site

Interim Response Action

  • DEP's responsibility under HSCA is to select a remedy that is protective of human health and the environment and complies with all statutory and regulatory requirements.
  • In May 2018, an Analysis of Alternatives and Proposed Response document was signed by DEP selecting the installation and maintenance of whole-house filtration systems as a proposed interim response to address the contamination of private drinking water wells associated with the Site. The information DEP used in formulating its proposal is incorporated into the Administrative Record.
  • The Administrative Record was open for public comment between June 2, 2018 and August 31, 2018.
  • Copies of the Administrative Record are available for public review at the DEP office in Norristown, and the East and West Rockhill Township Offices.
  • DEP held a public hearing on July 11, 2018 at the West Rockhill Township Building.
  • On April 18, 2019 DEP issued its Statement of Decision (SOD) and Response to Public Comments Documents.
    • In the SOD, DEP selected the Installation and Maintenance of Whole-House Filtration Systems (systems) combined with Restrictions on the Use of Groundwater, to address the threats posed by exposure to PFAS contamination above the EPA's HAL in residential privately-owned potable wells within the Site.
    • During the comment period DEP received multiple comments requesting that the duration of DEP's maintenance of the systems be extended beyond 12 months.
      • In response to these comments, at the end of this 12-month period, DEP will evaluate whether any of the circumstances exist that would allow an interim response to exceed 12 months in duration under the HSCA definition of "interim response" and, if so, whether the 12-month period should be extended accordingly.
      • Please note, Pennsylvania's Environmental Quality Board has not proposed a State Maximum Contaminant Level (MCL) before issuance of the SOD. If a State or Federal MCL is issued for PFOS or PFOA that is different from the HAL, DEP will reevaluate the Site, and will take action as necessary and appropriate.
    • Statement of Decision and Response to Public Comments (PDF)*
    • Response to Public Comments Appendices (PDF)*
  • *The documents were subsequently mailed to all individuals who commented on the proposed response.

Contacting DEP

To schedule an appointment to review files associated with this Site and project, please call the Norristown Office at 484-250-5910. Please direct correspondence or inquiries to one of the following:

Site Information: Colin Wade, Site Project Officer, at 484-250-5722 or

Community and Media Relations: Virginia Cain, Community Relations Coordinator at 484-250-5808 or

Legislative Inquiries: Rob Fogel, Local Government Liaison, at 484-250-5817 or

Municipality Information

East Rockhill Township: Phone: (215) 257-9156,

West Rockhill Township: Phone: (215) 257-9063,