PFAS test results
Highest average at any one sampling point, from EPA's UCMR 5 testing (2023–2025), against the levels EPA set in 2024. ND = not detected above EPA's reporting level. EPA's comparison rounds like this: an average of 4.05 ppt or more counts as above the 4 ppt PFOA/PFOS limit, and 15 ppt or more counts as above the 10 ppt level for PFHxS, PFNA and GenX.
Hazard index (PFHxS, PFNA, GenX, PFBS mix): 0.69 (limit 1, EPA comparison threshold 1.5).
All 10 detected compounds at this system (single highest result)
| Compound | Highest result | Results above reporting level |
|---|---|---|
| PFHxA | 43.5 ppt | 45 of 480 |
| PFPeA | 39.4 ppt | 53 of 480 |
| 6:2 FTS | 23.6 ppt | 2 of 480 |
| PFOS | 17.4 ppt | 13 of 480 |
| PFBA | 12.6 ppt | 9 of 480 |
| PFHxS | 10.8 ppt | 19 of 480 |
| PFHpA | 9.6 ppt | 4 of 480 |
| PFOA | 6.5 ppt | 19 of 480 |
| PFNA | 5.7 ppt | 2 of 480 |
| PFBS | 5.2 ppt | 5 of 480 |
Read this as a screening result, not a compliance finding. UCMR 5 samples are occurrence data. Legal compliance is judged on a running annual average from the utility's own monitoring, reported to the state. PFOA and PFOS at 4 ppt are in force; EPA has proposed to rescind the PFHxS, PFNA, GenX and hazard-index levels.
Violations and lead
No health-based violations began since 2021-10-26 in the EPA file for this system.
Lead 90th percentile: 1.0 ppb for the period ending 2025-12-31 (action level 15 ppb). This is a system-wide statistic, not your home's tap; lead usually comes from household plumbing and service lines.
What helps, and what does not
For PFAS, a point-of-use reverse-osmosis unit or a carbon filter certified to NSF/ANSI 53 or 58 for PFAS reduction is the realistic home step, with a lab test first. Be aware that today's certified claim is reduction to under 20 ppt combined PFAS, above the 4 ppt federal limit, so certification does not prove a filter reaches the federal level. Water softeners and iron filters do not remove PFAS. Read the whole-house PFAS answer.
Common questions
Is the tap water in Suffolk County Water Authority safe to drink?
At least one sampling point at Suffolk County Water Authority averaged above the 4 ppt federal limit: PFOA up to 6.0 ppt and PFOS up to 12 ppt. No health-based violations recorded since 2021-10-26. Lead 90th percentile 1.0 ppb in the sampling period ending 2025-12-31 (action level 15 ppb). This is a summary of public EPA data, not a guarantee about the water at your tap.
Does Suffolk County Water Authority have PFAS in its water?
Yes. EPA's 2023–2025 testing detected 10 of 29 PFAS compounds at Suffolk County Water Authority.
Not medical or legal advice. Results describe the utility's system, not your tap. Compare with your utility's annual Consumer Confidence Report.
Sources and freshness
Public-water-system facts, violations and lead/copper results: EPA ECHO SDWA download (SDWIS snapshot 2026-10-13). PFAS and lithium results: EPA UCMR 5 final data (sampling 2023–2025). Both are U.S. government works, downloaded 2026-10-26. Numbers are computed by the published method; the same fields are in the open data files.