PFAS detected in Pennsylvania water systems

EPA UCMR 5 monitoring (2023–2025) detected PFOA or PFOS at or above 6 parts per trillion in these 33 large Pennsylvania public water systems, each serving more than 10,000 people. Select a system to see exactly what was detected and the certified filters that reduce it.

Pennsylvania systems, highest detections first

Water system PFOA (ppt) PFOS (ppt) vs. 4 ppt reference
Emmaus Borough Public Water 22.4 153 38.3×
Horsham Water&Sewer Authority 17.5 33.8 8.4×
City of Lancaster, PA 23.8 — 6×
Northampton Bucks Co Mun Auth 19.6 23 5.8×
Aqua PA Hatboro 16.2 21.5 5.4×
Perkasie Regional Authority 6.5 17.6 4.4×
Paw Penn District 6.5 16.4 4.1×
Upper Southampton Mun Auth 14.2 16.4 4.1×
Ambler Boro Water Dept 15.3 13.7 3.8×
Quakertown Boro 10.8 14.3 3.6×
Gettysburg Muni Auth 7.4 14.1 3.5×
North Wales Water Authority 13 11.1 3.3×
Paw Glen Alsace Div 5.8 12.7 3.2×
Aqua PA Main System 12.6 9.2 3.1×
Newtown Artesian Water Co 12.3 7.9 3.1×
Muhlenberg Twp Muni Auth 8.8 11.5 2.9×
Suez Mechanicsburg 7.1 11.4 2.9×
Carlisle Water TRMT PLT 5 11.3 2.8×
PA American Royersford 9.1 10.7 2.7×
PA American Water Co West 4.9 10.4 2.6×
Moon Twp Muni Auth — 10 2.5×
PA American Water Co Yardley 9.7 6.1 2.4×
Dover Twp Water SYS 5.9 9.6 2.4×
Aqua PA Uwchlan 9.3 7.1 2.3×
Philadelphia Water Department 8.1 6 2×
Aqua PA Bensalem 8 7.5 2×
PA American Water Berwick 7.9 4 2×
East Hempfield Water Auth 7.7 5 1.9×
PA Amer Water Co Lake Scranton 4.9 7.6 1.9×
Warwick Twp Water & Sewer Auth 7.6 7.1 1.9×
Bcwsa Main Lower South 7.3 6.9 1.8×
Pittsburgh Intl Airport — 7 1.8×
Reading Area Water Authority 6.6 — 1.6×

Highest single EPA UCMR 5 detections (2023–2025), in parts per trillion. The last column is the multiple of the 4 ppt federal reference level for PFOA/PFOS — shown as context only, not a compliance or health determination. — means the compound was not detected at or above 6 ppt.

Not sure what's in your own water? Test it first, then run the selector for a recommendation matched to your home, or read what PFAS is and how it's removed.