Williamsport, PA · PFAS · forever chemicals
Is There PFAS in Williamsport Tap Water?
Williamsport, PA: PFOS 5.1 ng/L, 1.3× EPA's 4 ng/L limit. Every PFAS result and filter certifications per compound.
The measurements · EPA UCMR 5
5 of 29 PFAS detected
Each result is read against its own reference. Only PFOS, PFHxS and PFNA have federal limits. PFPeA has no federal or state limit and is shown for transparency, not graded.
- PFOSFederal MCLPerfluorooctanesulfonic acid5.1ng/LAbove its limit · sampled 2024-03-05 to 2024-12-10Evidence
- PFNAFederal MCLPerfluorononanoic acid9.7ng/LDetected, below its limit · limit under EPA review · sampled 2024-03-05 to 2024-12-10Evidence
- PFHxSFederal MCLPerfluorohexanesulfonic acid3.6ng/LDetected, below its limit · limit under EPA review · sampled 2024-03-05 to 2024-12-10Evidence
- PFHxAState MCL · MichiganPerfluorohexanoic acid3.5ng/LDetected, below its state limit · sampled 2024-03-05 to 2024-12-10Evidence
- PFPeANo limitPerfluoropentanoic acid4.1ng/L
No federal or state limit: shown for transparency, not graded.
Detected, no limit · sampled 2024-03-05 to 2024-12-10Evidence
All 29 compounds in this record
- PFOAMCLNot detected
- PFOSMCL5.1 ng/L
- PFHxSMCL3.6 ng/L
- PFNAMCL9.7 ng/L
- HFPO-DA (GenX)MCLNot detected
- PFHxA3.5 ng/L
- PFPeA4.1 ng/L
- 11Cl-PF3OUdSNot detected
- 4:2 FTSNot detected
- 6:2 FTSNot detected
- 8:2 FTSNot detected
- 9Cl-PF3ONSNot detected
- ADONANot detected
- NEtFOSAANot detected
- NFDHANot detected
- NMeFOSAANot detected
- PFBANot detected
- PFBSNot detected
- PFDANot detected
- PFDoANot detected
- PFEESANot detected
- PFHpANot detected
- PFHpSNot detected
- PFMBANot detected
- PFMPANot detected
- PFPeSNot detected
- PFTANot detected
- PFTrDANot detected
- PFUnANot detected
MCL marks the 5 PFAS given a federal limit in EPA's 2024 rule. EPA has proposed rescinding three of those limits; they apply until a final rule.
Results as a table29 results with limit, status, sample date and source
| Contaminant | Result | Limit | Status | Sampled | Source |
|---|---|---|---|---|---|
| Perfluorooctanesulfonic acid (PFOS) | 5.1 ng/L | 4.0 ng/L federal MCL (2024) | Above a historical reference; current applicability unverified | 2024-03-05 to 2024-12-10 | UCMR5 Analytical Results: WILLIAMSPORT MUN WATER AUTH (PA4410173) |
| Perfluorononanoic acid (PFNA) | 9.7 ng/L | 10 ng/L federal MCL (2024) | Within a historical reference; current applicability unverified | 2024-03-05 to 2024-12-10 | UCMR5 Analytical Results: WILLIAMSPORT MUN WATER AUTH (PA4410173) |
| Perfluorohexanesulfonic acid (PFHxS) | 3.6 ng/L | 10 ng/L federal MCL (2024) | Within a historical reference; current applicability unverified | 2024-03-05 to 2024-12-10 | UCMR5 Analytical Results: WILLIAMSPORT MUN WATER AUTH (PA4410173) |
| Perfluorohexanoic acid (PFHxA) | 3.5 ng/L | 400,000 ng/L Michigan EGLE state MCL (strictest US state) | Within a historical reference; current applicability unverified | 2024-03-05 to 2024-12-10 | UCMR5 Analytical Results: WILLIAMSPORT MUN WATER AUTH (PA4410173) |
| Perfluoropentanoic acid (PFPeA) | 4.1 ng/L | No federal or state limit; shown for transparency | Detected, no limit | 2024-03-05 to 2024-12-10 | UCMR5 Analytical Results: WILLIAMSPORT MUN WATER AUTH (PA4410173) |
| 11-Chloroeicosafluoro-3-oxaundecane-1-sulfonic acid (11Cl-PF3OUdS) | < 5 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-03-05 to 2024-12-10 | UCMR5 Analytical Results: WILLIAMSPORT MUN WATER AUTH (PA4410173) |
| 1H, 1H, 2H, 2H-perfluorodecane sulfonic acid (8:2 FTS) | < 5 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-03-05 to 2024-12-10 | UCMR5 Analytical Results: WILLIAMSPORT MUN WATER AUTH (PA4410173) |
| 1H, 1H, 2H, 2H-perfluorohexane sulfonic acid (4:2 FTS) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-03-05 to 2024-12-10 | UCMR5 Analytical Results: WILLIAMSPORT MUN WATER AUTH (PA4410173) |
| 1H, 1H, 2H, 2H-perfluorooctane sulfonic acid (6:2 FTS) | < 5 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-03-05 to 2024-12-10 | UCMR5 Analytical Results: WILLIAMSPORT MUN WATER AUTH (PA4410173) |
| 4,8-Dioxa-3H-perfluorononanoic acid (ADONA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-03-05 to 2024-12-10 | UCMR5 Analytical Results: WILLIAMSPORT MUN WATER AUTH (PA4410173) |
| 9-Chlorohexadecafluoro-3-oxanone-1-sulfonic acid (9Cl-PF3ONS) | < 2 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-03-05 to 2024-12-10 | UCMR5 Analytical Results: WILLIAMSPORT MUN WATER AUTH (PA4410173) |
| Hexafluoropropylene oxide dimer acid (HFPO-DA) (GenX chemicals) | < 5 ng/L | 10 ng/L federal MCL (2024) | Not detected above the reporting limit | 2024-03-05 to 2024-12-10 | UCMR5 Analytical Results: WILLIAMSPORT MUN WATER AUTH (PA4410173) |
| N-ethyl perfluorooctanesulfonamidoacetic acid (NEtFOSAA) | < 5 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-03-05 to 2024-12-10 | UCMR5 Analytical Results: WILLIAMSPORT MUN WATER AUTH (PA4410173) |
| N-methyl perfluorooctanesulfonamidoacetic acid (NMeFOSAA) | < 6 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-03-05 to 2024-12-10 | UCMR5 Analytical Results: WILLIAMSPORT MUN WATER AUTH (PA4410173) |
| Nonafluoro-3,6-dioxaheptanoic acid (NFDHA) | < 20 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-03-05 to 2024-12-10 | UCMR5 Analytical Results: WILLIAMSPORT MUN WATER AUTH (PA4410173) |
| Perfluoro (2-ethoxyethane) sulfonic acid (PFEESA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-03-05 to 2024-12-10 | UCMR5 Analytical Results: WILLIAMSPORT MUN WATER AUTH (PA4410173) |
| Perfluoro-3-methoxypropanoic acid (PFMPA) | < 4 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-03-05 to 2024-12-10 | UCMR5 Analytical Results: WILLIAMSPORT MUN WATER AUTH (PA4410173) |
| Perfluoro-4-methoxybutanoic acid (PFMBA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-03-05 to 2024-12-10 | UCMR5 Analytical Results: WILLIAMSPORT MUN WATER AUTH (PA4410173) |
| Perfluorobutanesulfonic acid (PFBS) | < 3 ng/L | 2,000 ng/L EPA health advisory (screening, not a legal limit)Screening level, not a legal limit | Not detected above the reporting limit | 2024-03-05 to 2024-12-10 | UCMR5 Analytical Results: WILLIAMSPORT MUN WATER AUTH (PA4410173) |
| Perfluorobutanoic acid (PFBA) | < 5 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-03-05 to 2024-12-10 | UCMR5 Analytical Results: WILLIAMSPORT MUN WATER AUTH (PA4410173) |
| Perfluorodecanoic acid (PFDA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-03-05 to 2024-12-10 | UCMR5 Analytical Results: WILLIAMSPORT MUN WATER AUTH (PA4410173) |
| Perfluorododecanoic acid (PFDoA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-03-05 to 2024-12-10 | UCMR5 Analytical Results: WILLIAMSPORT MUN WATER AUTH (PA4410173) |
| Perfluoroheptanesulfonic acid (PFHpS) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-03-05 to 2024-12-10 | UCMR5 Analytical Results: WILLIAMSPORT MUN WATER AUTH (PA4410173) |
| Perfluoroheptanoic acid (PFHpA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-03-05 to 2024-12-10 | UCMR5 Analytical Results: WILLIAMSPORT MUN WATER AUTH (PA4410173) |
| Perfluorooctanoic acid (PFOA) | < 4 ng/L | 4.0 ng/L federal MCL (2024) | Not detected above the reporting limit | 2024-03-05 to 2024-12-10 | UCMR5 Analytical Results: WILLIAMSPORT MUN WATER AUTH (PA4410173) |
| Perfluoropentanesulfonic acid (PFPeS) | < 4 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-03-05 to 2024-12-10 | UCMR5 Analytical Results: WILLIAMSPORT MUN WATER AUTH (PA4410173) |
| Perfluorotetradecanoic acid (PFTA) | < 8 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-03-05 to 2024-12-10 | UCMR5 Analytical Results: WILLIAMSPORT MUN WATER AUTH (PA4410173) |
| Perfluorotridecanoic acid (PFTrDA) | < 7 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-03-05 to 2024-12-10 | UCMR5 Analytical Results: WILLIAMSPORT MUN WATER AUTH (PA4410173) |
| Perfluoroundecanoic acid (PFUnA) | < 2 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-03-05 to 2024-12-10 | UCMR5 Analytical Results: WILLIAMSPORT MUN WATER AUTH (PA4410173) |
How this compares
PFOS across 764 cities with a detected value
Williamsport 5.14 ng/L federal MCL (2024)
3,396 more were below the lab's 4 ng/L reporting limit and aren't plotted, and 34 have no result on record. 66 cities above 25 ng/L are grouped in the last bar. A position here is not a verdict on the water.
Where Williamsport sits5.1 ng/L PFOSLower than 75% of 764 cities with a detected value.
In Pennsylvania
41of 122 city reports
have a regulated PFAS above the federal limit.
PFAS across Pennsylvania →What this record covers
- WILLIAMSPORT MUN WATER AUTH's water system as a whole, as reported to EPA UCMR 5.
- 29 PFAS compounds, each with its own result.
- Samples taken 2024-03-05 to 2024-12-10.
What is unknown
- The water at your tap. Building plumbing isn't in this record.
- PFAS not listed in the 29 above were not reported in these records.
- Levels since the last sample have not been published.
Treatment capabilities that apply
Test first, then match a certified method.
A tap test can confirm levels at your home before you choose treatment.
Identified concerns
- PFOS · exceeds the limit
- PFHxA · detected below the limit
- PFHxS · detected below the limit
- PFNA · detected below the limit
- PFPeA · detected, no federal or state limit
- Reverse osmosisOpen the method →
- Activated carbon (GAC)Open the method →
- Anion exchangeOpen the method →
9 products have a current certification naming a PFAS detected here.See PFAS filters, checked compound by compound ↓
Commercial · PFAS filters
Fit for Williamsport’s PFAS, compound by compound
Each filter is checked against the 5 PFAS detected here. A ✓ needs a current certification record that names the compound. A PFAS claim on the box is not enough.
As an Amazon Associate, PurityMap earns from qualifying purchases. A product appears here only when a current certification record covers at least one identified concern; every concern stays listed. The retail offer is looked up afterwards and never changes which products appear or their order. Affiliate disclosure.
- ✓Certified for this compound
- ?Claimed or likely, not established
- –No claim on record
Under-Sink Filter
Aquasana Claryum 2-Stage Under-Sink Filter (AQ-5200)
Activated Carbon (Claryum)Detected in Williamsport1 of 5 certified
- PFOS5.1 ng/L✓Certified for this compound
- PFHxA3.5 ng/L–No claim on record
- PFHxS3.6 ng/L–No claim on record
- PFNA9.7 ng/L–No claim on record
- PFPeA4.1 ng/L–No claim on record
CertifiedNSF/ANSI 53 · PFOA, PFOS
Certified for PFOS; not established for PFHxA, PFHxS, PFNA, PFPeA.
Under-Sink Filter
Aquasana Claryum 3-Stage Max Flow Under-Sink Filter (AQ-6300M)
Activated Carbon (Claryum)Detected in Williamsport1 of 5 certified
- PFOS5.1 ng/L✓Certified for this compound
- PFHxA3.5 ng/L–No claim on record
- PFHxS3.6 ng/L–No claim on record
- PFNA9.7 ng/L–No claim on record
- PFPeA4.1 ng/L–No claim on record
CertifiedNSF/ANSI 53 · PFOA, PFOSNSF/ANSI 42
Certified for PFOS; not established for PFHxA, PFHxS, PFNA, PFPeA.
Countertop System
Aquasana Clean Water Machine Countertop Filter (AQ-CWM2)
Activated Carbon (Claryum)Detected in Williamsport1 of 5 certified
- PFOS5.1 ng/L✓Certified for this compound
- PFHxA3.5 ng/L–No claim on record
- PFHxS3.6 ng/L–No claim on record
- PFNA9.7 ng/L–No claim on record
- PFPeA4.1 ng/L–No claim on record
CertifiedNSF/ANSI 53 · PFOA, PFOSNSF/ANSI 42
Certified for PFOS; not established for PFHxA, PFHxS, PFNA, PFPeA.
Countertop System
Patriot Pure Ultimate Water Filtration System
Gravity pour-through (Nanomesh filter)Detected in Williamsport1 of 5 certified
- PFOS5.1 ng/L✓Certified for this compound
- PFHxA3.5 ng/L–No claim on record
- PFHxS3.6 ng/L–No claim on record
- PFNA9.7 ng/L–No claim on record
- PFPeA4.1 ng/L–No claim on record
CertifiedNSF/ANSI 53 · PFOA, PFOS
Certified for PFOS; not established for PFHxA, PFHxS, PFNA, PFPeA.
Countertop System
AquaTru Carafe Countertop Reverse-Osmosis Purifier (AT100)
Reverse OsmosisDetected in Williamsport1 of 5 certified
- PFOS5.1 ng/L✓Certified for this compound
- PFHxA3.5 ng/L–No claim on record
- PFHxS3.6 ng/L–No claim on record
- PFNA9.7 ng/L–No claim on record
- PFPeA4.1 ng/L–No claim on record
CertifiedNSF/ANSI 58NSF/ANSI 53 · PFOA, PFOSNSF/ANSI 42
Certified for PFOS; not established for PFHxA, PFHxS, PFNA, PFPeA.
Countertop System
AquaTru Classic Countertop Reverse-Osmosis Purifier (AT2000)
Reverse OsmosisDetected in Williamsport1 of 5 certified
- PFOS5.1 ng/L✓Certified for this compound
- PFHxA3.5 ng/L–No claim on record
- PFHxS3.6 ng/L–No claim on record
- PFNA9.7 ng/L–No claim on record
- PFPeA4.1 ng/L–No claim on record
CertifiedNSF/ANSI 58NSF/ANSI 53 · PFOA, PFOSNSF/ANSI 42
Certified for PFOS; not established for PFHxA, PFHxS, PFNA, PFPeA.
Under-Sink Filter
Waterdrop G3P600 Tankless Reverse-Osmosis System
Reverse OsmosisDetected in Williamsport1 of 5 certified
- PFOS5.1 ng/L✓Certified for this compound
- PFHxA3.5 ng/L–No claim on record
- PFHxS3.6 ng/L–No claim on record
- PFNA9.7 ng/L–No claim on record
- PFPeA4.1 ng/L–No claim on record
CertifiedNSF/ANSI 58NSF/ANSI 53 · PFOA, PFOSNSF/ANSI 42
Certified for PFOS; not established for PFHxA, PFHxS, PFNA, PFPeA.
Under-Sink Filter
Waterdrop G3P800 Tankless Reverse-Osmosis System
Reverse OsmosisDetected in Williamsport1 of 5 certified
- PFOS5.1 ng/L✓Certified for this compound
- PFHxA3.5 ng/L–No claim on record
- PFHxS3.6 ng/L–No claim on record
- PFNA9.7 ng/L–No claim on record
- PFPeA4.1 ng/L–No claim on record
CertifiedNSF/ANSI 53 · PFOA, PFOSNSF/ANSI 58NSF/ANSI 42
Certified for PFOS; not established for PFHxA, PFHxS, PFNA, PFPeA.
Refrigerator Filter
Whirlpool Filter 3 Refrigerator Water Filter (WHR3RXD1)
Activated CarbonDetected in Williamsport1 of 5 certified
- PFOS5.1 ng/L✓Certified for this compound
- PFHxA3.5 ng/L–No claim on record
- PFHxS3.6 ng/L–No claim on record
- PFNA9.7 ng/L–No claim on record
- PFPeA4.1 ng/L–No claim on record
CertifiedNSF/ANSI 53 · PFOA, PFOSNSF/ANSI 42NSF/ANSI 401
Certified for PFOS; not established for PFHxA, PFHxS, PFNA, PFPeA.
- Browse, not a match:
- Brita Elite Water Filter Pitcher
- Clearly Filtered Pitcher (lab-tested, not NSF 53 certified)
- Culligan ZeroWater 10-Cup Pitcher (ZEROP10)
- Frizzlife SP99 Under-Sink Filter
None of these is certified for all 5 compounds detected here. A tap test first tells you which ones reach your glass.
Questions
Frequently asked
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Is there PFAS in Williamsport tap water?
In EPA's UCMR 5 testing of WILLIAMSPORT MUN WATER AUTH (2024-03-05 to 2024-12-10): PFHxA 3.5 ng/L (state limit 400,000), PFHxS 3.6 ng/L (limit 10), PFNA 9.7 ng/L (limit 10), PFOS 5.1 ng/L (limit 4), PFPeA 4.1 ng/L (no federal or state limit) and the other 24 PFAS tested not detected. "Not detected" means below the lab's reporting limit, not proven zero.
What are the federal PFAS limits?
EPA's 2024 drinking-water rule set maximum contaminant levels of 4.0 ng/L for PFOA and for PFOS, and 10 ng/L for PFHxS, PFNA and HFPO-DA (GenX). In May 2026 EPA proposed keeping the PFOA and PFOS limits, with the option of until 2031 to comply, and rescinding the other three. Until a final rule, all five limits apply. Results above them today are above the limits in force.
How do I remove PFAS from my tap water?
Reverse-osmosis systems and filters certified to NSF/ANSI 53 or 58 for PFOA/PFOS reduction are the proven options at the tap. Check the certifier's listing (NSF, WQA or IAPMO) for the exact model, and replace cartridges on schedule.
- UCMR5 Analytical ResultsUCMR5 Analytical Results: WILLIAMSPORT MUN WATER AUTH (PA4410173)US EPA · 2026-01-15View source ↗
- State SDWIS Compliance RecordLead & Copper Rule 90th-percentile: WILLIAMSPORT MUN WATER AUTH (PA4410173)US EPA SDWIS · 2026-07-09View source ↗