Ridge Run PFAS Site
For more information on PFAS contaminants, what Pennsylvania is doing on a state level, Governor Wolf’s PFAS Action Team, and more, please visit:
Municipality/County: East and West Rockhill Townships, Bucks County
HSCA Site Since: 2016
Primary Contaminants of Concern:
perfluorooctanoic acid (PFOA) & perfluorooctane sulfonate (PFOS)
Updated October 2021
Why is DEP Investigating?
- In November, 2016, a public supply well in the area was found to contain combined concentrations of PFOA and PFOS that exceeded Environmental Protection Agency’s (EPA) 70 parts per trillion (ppt) Health Advisory Level (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.
- 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 take action as necessary and appropriate.
- DEP is investigating groundwater in the area to determine the extent of PFOA and PFOS in the aquifer underlying the area.
Private Drinking Water Investigation and DEP's Response
- 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.
- 15 homes have been identified as having PFAS levels above the HAL. Those homes were initially provided bottled water from DEP or elected to independently install carbon filtration systems.
- 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.
- DEP determined the most appropriate interim response action to be the installation of ion exchange (resin) systems.
- The response of treatment systems was formally selected in DEP's Statement of Decision (SOD) and Response to Public Comments Document, which was issued on April 18, 2019. 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.
- The Administrative Record was open for public comment between June 2, 2018 and August 31, 2018.
Ridge Run Administrative Record (PDF)
*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.
Statement of Decision and Response to Public Comments (PDF)
Response to Public Comments Appendices (PDF)
- DEP considers this response to be an interim response as additional actions may be needed to achieve a complete and final cleanup for the site.
- DEP plans to install Ion Exchange (Resin) Treatment Systems to remove PFAS from drinking water. According to available data, Resin Treatment Systems have been proven to be effective for PFAS removal. The initial cost, which will be covered by DEP, is generally higher than other treatment systems; however, the system requires less maintenance than other treatment systems, leading to lower operating costs. The resins are currently certified for use in drinking water under NSF/ANSI-61 standard.
- Since the issuance of the SOD, DEP determined that the necessary circumstances already exist to allow its interim response to exceed 12 months in duration.
Based on that determination, DEP no longer plans to transfer maintenance of the filtration systems to the residents after the 12-month period. Instead, DEP plans to monitor and maintain the systems to ensure that they are working properly for the duration of its investigation of the Site.
- As of March 2021, DEP has installed systems at 11 of the 15 homes with PFAS levels above the HAL.
- Post treatment samples collected to date have indicated that the DEP-installed treatment systems are removing PFAS contamination from the drinking water supplies to below the HAL.
Source Investigation (updated March 2021)
DEP is looking into all potentially responsible parties. If you have any information related to any potential sources of PFAS contamination, please feel free to provide that information to DEP using the contact information provided below.
- In April 2019 - DEP conducted soil and surface water sampling at the site. DEP utilized the results of the sampling to help determine the best locations for the planned monitoring wells.
- In July and August 2019, DEP drilled 6 monitoring wells throughout the area of concern.
- In mid-August 2019, DEP collected additional surface water, sediment, and soil samples. There were detections of PFOA and PFOS in the samples. DEP will continue evaluating the data as part of its ongoing source investigation.
- In 2019, DEP informed Bergey’s that PFAS were detected on their property and informed them of their potential responsibility
Site Inspection Report (PDF) March 2020 prepared by EnviroTrac, Ltd on behalf of DEP.
- In August 2020, DEP conducted surface water sampling at the Site in the aftermath of Tropical Storm Isaias to determine if elevated concentrations of PFAS had entered Threemile Run from the Site. Those results did not find elevated concentrations of PFAS entering Threemile Run.
- In October 2020, DEP drilled 3 additional monitoring wells throughout the area of concern.
- DEP performed sampling of the monitoring wells across the Site in December 2020. Those results can be found here:
Pilot Study (New March 2021)
In an attempt to prevent the further spread of PFOS and PFOA from the source area into nearby residential wells, DEP and its contractors will be conducting a pilot study. The study is focused on the use of a product known as PlumeStop®, manufactured by Regenesis, to create a permeable, reactive underground barrier, which will allow groundwater to flow through it, but not PFOS and PFOA.
- The results of the first three post-injection sampling events show significant reductions of PFOA and PFOS in monitoring wells within the study area.
- DEP and its contractors will continue to perform groundwater sampling determine the success of the pilot study. Updates on the pilot study will be posted on this website in the future.
To subscribe to updates, please send an email to: RA-EP-SEROECB@pa.gov.
Please indicate in the subject line or text of the email that you’d like to receive updates related to the Ridge Run PFAS HSCA Site.
- October 21, 2021
March 17, 2021
October 9, 2020
August 17, 2020
March 25, 2020
March 16, 2020
February 6, 2020
December 20, 2019
November 27, 2019
November 12, 2019
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 Nurk, Community Relations Coordinator at 484-250-5808 or
Legislative Inquiries: Rob Fogel, Local Government Liaison, at 484-250-5817 or
To schedule an appointment to review files associated with this Site and project, please call the Norristown Office at 484-250-5910.
East Rockhill Township: Phone: (215) 257-9156,
West Rockhill Township: Phone: (215) 257-9063,