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HWSA Public Water Supply PFAS Test Results

January 2023 Update

Since 2014 HWSA has been performing ongoing testing for Perfluorooctanoic acid (PFOA) and Perfluorooctanesulfonic acid (PFOS) in all of its wells.  All analyses are performed by certified laboratories using EPA Method 537.  This method yields individual concentrations for anywhere between 6 and 14 different PFAS compounds depending on the laboratory, but PFOA and PFOS are always among the results.  To date, the Authority has accumulated over 10,000 results for the various PFAS compounds that can be analyzed under Method 537.  In an effort to ensure readability of the information, our previously published data included values only for PFOA and PFOS as these were the only two PFAS compounds that had existing Health Advisories (HA) in place, either federally or in Pennsylvania.

In December 2018, the Pennsylvania  Department of Health released results from random voluntary blood testing in this area and found elevated concentrations of  PFOA, PFOS, Perfluorohexanesulfonic  acid (PFHxS), and Perfluorononanoic acid (PFNA) in the blood tests from people in the Horsham/Warminster/Warrington area as compared to the US population at large.  Accordingly, the presentation of our well sampling data has been modified and now includes results for the two additional compounds, PFHxS and PFNA.  For wells that have PFAS treatment in place, graphs are presented showing the concentration of PFOS, PFOA, PFHxS, and PFNA in  both the raw untreated well water, as well as  the treated water, which is representative of the quality of water entering the drinking water system.

In addition to the 4 PFAS compounds for which data is being presented in graphs on our website, the current analytical method provides data for 10 additional PFAS compounds.  However, based on our extensive sampling, only 3 additional PFAS compounds are found in our untreated groundwater at levels above the current  analytical detection levels (~2.5 parts per trillion per compound).  These 3 compounds are Perfluorobutanesulfonic acid (PFBS),  Perfluorohexanoic acid (PFHxA) and  Perfluoroheptanoic acid (PFHpA).   Data for these 3 compounds can be found on our website in the tabular data but are not included on the graphs in order to keep the graphs from becoming too busy.  When results are not found at levels above the analytical detection level, the results are listed as ND (for “not detected”) to signify that the results are not necessarily zero, just below the level the laboratory can currently detect. 

When viewing the PFAS data below, note that the data is presented in links based on the individual sources (either HWSA wells or interconnections with neighboring utilities) and the links are listed as either active (currently being utilized for drinking water) or inactive (source not currently being utilized for drinking water).  The sources that have PFAS removal treatment installed, will have 2 links: one for the untreated groundwater prior to PFAS removal treatment (raw), and one for the filtered water that is actually being pumped into the drinking water system (treated).

Anyone interested in reviewing all available data is also welcome to do so by contacting our office at 215-672-8011 and setting up an appointment.  

Active Sources

Inactive Sources

Here are the facts about the Occurrence and HWSA management  of short-chain PFAS compounds

**Due to the signifigant size of lab report data files, we are unable to post them on our website. Lab reports for all PFAS monitoring of the public water supply are available by visiting the Authority's office located at 617 Horsham Road Monday through Friday 9AM to 4PM.