PFAS in Drinking Water in Pennsylvania
What residents of Pennsylvania need to know about PFAS ("forever chemicals") in drinking water — including contamination sources, which utilities have documented violations, and how to filter PFAS from tap water.
Source: EPA SDWIS, Pennsylvania Department of Environmental Protection, CDC · Last reviewed: 2025-01-01
Quick Answer
Is PFAS in drinking water a real concern in Pennsylvania?
Yes — Pennsylvania has widespread PFAS contamination from multiple military installations, industrial sources, and legacy manufacturing. Willow Grove Naval Air Station (now a Guard base), Horsham Air Guard Station, and the former Naval Air Warfare Center Warminster are among the most significant sources, directly contaminating drinking water for tens of thousands of Montgomery and Bucks County residents north of Philadelphia.
Where does PFAS come from in Pennsylvania?
The cluster of former military installations in southeastern Pennsylvania — Horsham Air Guard Station, former Willow Grove NAS, and the former Warminster Naval Air Warfare Center — have contaminated groundwater for a wide swath of Montgomery and Bucks counties. PFAS-contaminated water has been detected in multiple public water systems and private wells in these densely populated Philadelphia suburbs. Additional contamination sources include industrial sites in the Reading/Allentown corridor and Pittsburgh's industrial west.
What should Pennsylvania residents know?
The Philadelphia suburban contamination belt in Montgomery and Bucks counties is one of the most significant military PFAS impacts on a civilian population in the U.S. Multiple water utilities — Horsham Water and Sewer Authority, Warminster Municipal Authority, Warrington Township, and others — have documented PFAS contamination and installed treatment or switched sources. Pennsylvania DEP has been actively engaged with affected utilities and the Navy on remediation funding.
Key Facts
| EPA MCL (PFOA/PFOS) | 4 ppt — effective April 2024 |
| MCLG | Zero |
| Primary contamination sources | Horsham ANG, former Willow Grove NAS, former Warminster NAWC (all Montgomery/Bucks counties) |
| Scale of impact | Hundreds of thousands of residents in Philadelphia suburbs served by contaminated water systems |
| State regulator | Pennsylvania Department of Environmental Protection (PA DEP) |
| Treatment status | Multiple PA utilities have installed GAC treatment — funded partly by federal remediation programs |
| Health effects | Cancer (kidney, testicular), thyroid disruption, immune effects, developmental toxicity |
| Effective treatment | GAC (installed at multiple SE Pennsylvania utilities) or RO for household use |
Why PFAS Matters in Pennsylvania
Pennsylvania's southeastern PFAS crisis is one of the most consequential in the nation. The former military installations north of Philadelphia — Horsham, Willow Grove, and Warminster — have contaminated groundwater for communities with a combined population of hundreds of thousands. Some utilities have detected PFAS at levels many times the EPA's new 4 ppt MCL. The Navy has been engaged in remediation discussions and has provided some funding for treatment installation, though advocates argue the response has been insufficient. This cluster of contaminated communities became a focal point in national advocacy for PFAS regulation and has been cited repeatedly in Congressional hearings.
Historical Context
The Horsham/Warminster cluster became one of the most visible PFAS contamination crises in the country after local residents and advocates documented contaminated well water and organized to demand federal action. Community groups in these Philadelphia suburbs were instrumental in advocating for EPA's PFAS MCL rulemaking and congressional PFAS legislation.
Pennsylvania PFAS Regulation
Pennsylvania DEP participates in UCMR5 monitoring and has assessed PFAS at Willow Grove NAS (now closed), the Horsham/Warminster area (one of the most extensively documented civilian PFAS crises nationally), and multiple other bases. The Horsham area — north of Philadelphia — had drinking water wells contaminated by AFFF from Willow Grove and Horsham Air Guard Station, affecting tens of thousands of residents. Pennsylvania does not have a state MCL more protective than federal but has an active PFAS investigation program.
Largest Pennsylvania Water Utilities
No PFAS violations on record in EPA SDWIS for Pennsylvania utilities in our database. Browse the largest utilities to review their full water quality record.
What Are PFAS (“Forever Chemicals”)?
PFAS are a family of over 12,000 synthetic chemicals used in non-stick cookware, stain-resistant fabrics, food packaging, and AFFF firefighting foam. Their carbon-fluorine bonds do not break down in the environment or the body — hence the name “forever chemicals.” AFFF used at military bases is the single largest source of PFAS in U.S. drinking water.
Full PFAS overview — national data, health effects, all 50 statesWho Should Pay Closest Attention
Residents of Horsham Township, Warminster Township, Warrington Township, and surrounding Bucks and Montgomery county communities served by utilities that draw from PFAS-contaminated groundwater face the highest documented risk. Private well users in southeastern Pennsylvania near these former military installations should test immediately.
Residents near military bases with AFFF use history
Private well owners near military or industrial sites
Pregnant residents and families with young children
Residents in communities with documented PFAS detections
Anyone who has consumed water above 4 ppt for an extended period
Residents near airports, fire training areas, or industrial manufacturers
How to Check Your Situation in Pennsylvania
- 1
Identify your water utility using the ZIP lookup below or by browsing the Pennsylvania utility directory on this site.
- 2
Review your utility's Consumer Confidence Report (CCR) — it must report PFAS monitoring results under UCMR5 and the new MCL.
- 3
Check the EPA's ECHO database for your utility's monitoring history. Look for PFAS, PFOA, PFOS, and related compound results.
- 4
Contact your utility directly and ask for their most recent PFAS test results and whether they are implementing treatment under the 2024 MCL.
- 5
If you use a private well near a military base, airport, or industrial facility, order a PFAS panel test from a state-certified laboratory. Tests typically cost $150–$400.
- 6
If PFAS is detected above 4 ppt in your source water, install a certified NSF/ANSI 58 reverse osmosis system or an NSF/ANSI 53-certified activated carbon filter rated for PFAS removal.
How to Remove PFAS from Tap Water
Reverse Osmosis (Best)
90–99% removal — NSF/ANSI 58 certified systems only
Certified Activated Carbon
Effective with NSF/ANSI 53 or 58 certification — verify before buying
Boiling concentrates PFAS. Standard pitcher filters and water softeners do not remove PFAS. Always verify NSF certification before purchasing.
Take Action Now
Look up your Pennsylvania utility's PFAS monitoring history on the PFAS Watchlist below.
If your utility has detected PFAS above 4 ppt, install an NSF/ANSI 58-certified reverse osmosis system at your drinking tap.
Private well owners near military or industrial sites should order a PFAS panel test ($150–$400 at a state-certified lab).
Request your utility's most recent Consumer Confidence Report — PFAS results must be disclosed under the new 2024 MCL.
Frequently Asked Questions
Related Pages
PFAS — National Overview
All U.S. utilities with PFAS records
Pennsylvania PFAS Watchlist
Live utility PFAS monitoring data
Pennsylvania State Overview
All utilities and water quality data
Reverse Osmosis Guide
Removes 90–99% of PFAS
Activated Carbon Filter Guide
NSF/ANSI 53/58 certified options for PFAS
Arsenic in Drinking Water
Another priority contaminant
All Contaminants
Complete reference library
Data Sources & Provenance
All data on this page is sourced from official U.S. government or public datasets.
Find Your Utility
State Regulator
Pennsylvania Department of Environmental Protection ↗