This page summarizes EPA Fifth Unregulated Contaminant Monitoring Rule (UCMR 5, 2023–2025) drinking-water monitoring records linked to ZIP codes in Maine, as processed for the PFAS Estimator national dataset. Data updated: July 2026.
| Compound | Applicable threshold | ZIP codes detected | At/above threshold | Mean detected | Maximum detected |
|---|---|---|---|---|---|
| PFOA | 0.004 µg/L (MCL) | 11 (52.4% of state) | 11 (100.0%) — all detections at/above limit by construction | 0.007 µg/L | 0.0092 µg/L |
| PFOS | 0.004 µg/L (MCL) | 2 (9.5% of state) | 2 (100.0%) — all detections at/above limit by construction | 0.0071 µg/L | 0.0071 µg/L |
| PFHxS | 0.01 µg/L (MCL) | 5 (23.8% of state) | 1 (20.0% of detected) | 0.0055 µg/L | 0.0132 µg/L |
| PFBS | 2.0 µg/L (HI reference) | 1 (4.8% of state) | not calculated¹ | 0.0093 µg/L | 0.0093 µg/L |
| Lithium | 7.36 µg/L (reference, not a regulatory limit) | 8 (38.1% of state) | 8 (100.0%) at/above reference | 15.7575 µg/L | 33.0 µg/L |
| PFPeA | — (no federal limit) | 9 (42.9% of state) | — | 0.0072 µg/L | 0.0107 µg/L |
| PFBA | — (no federal limit) | 12 (57.1% of state) | — | 0.0063 µg/L | 0.0068 µg/L |
| PFHpA | — (no federal limit) | 10 (47.6% of state) | — | 0.0049 µg/L | 0.0054 µg/L |
21 ZIP codes with at least one recorded PFAS detection. Click a ZIP code to view its full compound-level results.
| ZIP code | Compounds detected | At/above threshold |
|---|---|---|
| 04011 | 1 | No |
| 04021 | 4 | Yes (1) |
| 04042 | 1 | No |
| 04048 | 1 | No |
| 04061 | 1 | No |
| 04073 | 6 | Yes (2) |
| 04083 | 6 | Yes (2) |
| 04086 | 1 | No |
| 04096 | 4 | Yes (1) |
| 04097 | 4 | Yes (1) |
| 04252 | 5 | Yes (2) |
| 04345 | 2 | No |
| 04609 | 1 | No |
| 04634 | 3 | No |
| 04785 | 1 | No |
| 04901 | 3 | Yes (1) |
| 04915 | 2 | No |
| 04937 | 3 | Yes (1) |
| 04962 | 3 | Yes (1) |
| 04975 | 3 | Yes (1) |
| 04989 | 3 | Yes (1) |
Results are based on EPA UCMR 5 monitoring data (2023–2025), linked to ZIP codes via Public Water System Identifier. Non-detections are not present in this analytic dataset. For each compound and ZIP code, the highest observed concentration across the monitoring period is retained; this characterizes the upper bound of observed drinking-water concentrations, not a long-term average or an individual exposure estimate. A single water system may serve multiple ZIP codes, so the same monitoring record can appear for more than one ZIP in this table. ZIP-code assignment reflects water-system service area geography and does not establish individual household exposure. Private wells are not represented unless served by a monitored public water system. PFOA and PFOS are reported by detection prevalence because the UCMR 5 reporting limit equals their federal MCL. A full PFBS Hazard Index is not calculated because co-located, same-event multi-compound readings are not retained in this dataset. Lithium has no federal Maximum Contaminant Level; 7.36 µg/L is an evidence-based reference concentration from a prospective cohort study, not a regulatory threshold.
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