This page summarizes EPA Fifth Unregulated Contaminant Monitoring Rule (UCMR 5, 2023–2025) drinking-water monitoring records linked to ZIP codes in Alaska, 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) | 26 (83.9% of state) | 26 (100.0%) — all detections at/above limit by construction | 0.0074 µg/L | 0.0091 µg/L |
| PFOS | 0.004 µg/L (MCL) | 1 (3.2% of state) | 1 (100.0%) — all detections at/above limit by construction | 0.0463 µg/L | 0.0463 µg/L |
| PFHxS | 0.01 µg/L (MCL) | 29 (93.5% of state) | 23 (79.3% of detected) | 0.0104 µg/L | 0.0185 µg/L |
| Lithium | 7.36 µg/L (reference, not a regulatory limit) | 1 (3.2% of state) | 1 (100.0%) at/above reference | 9.01 µg/L | 9.01 µg/L |
| PFPeA | — (no federal limit) | 16 (51.6% of state) | — | 0.0039 µg/L | 0.006 µg/L |
| PFBA | — (no federal limit) | 2 (6.5% of state) | — | 0.0243 µg/L | 0.0371 µg/L |
| PFHpA | — (no federal limit) | 1 (3.2% of state) | — | 0.0039 µg/L | 0.0039 µg/L |
31 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 |
|---|---|---|
| 99501 | 2 | Yes (2) |
| 99502 | 2 | Yes (2) |
| 99503 | 2 | Yes (2) |
| 99504 | 2 | Yes (2) |
| 99507 | 2 | Yes (2) |
| 99508 | 2 | Yes (2) |
| 99515 | 2 | Yes (2) |
| 99516 | 2 | Yes (2) |
| 99517 | 2 | Yes (2) |
| 99567 | 2 | Yes (2) |
| 99574 | 1 | No |
| 99577 | 2 | Yes (2) |
| 99654 | 1 | No |
| 99669 | 1 | No |
| 99701 | 3 | Yes (2) |
| 99702 | 3 | Yes (1) |
| 99703 | 1 | No |
| 99705 | 3 | Yes (2) |
| 99706 | 3 | Yes (2) |
| 99707 | 3 | Yes (2) |
| 99708 | 3 | Yes (2) |
| 99709 | 3 | Yes (2) |
| 99710 | 3 | Yes (2) |
| 99711 | 3 | Yes (2) |
| 99712 | 3 | Yes (2) |
| 99714 | 3 | Yes (1) |
| 99716 | 3 | Yes (2) |
| 99723 | 5 | Yes (2) |
| 99767 | 3 | Yes (1) |
| 99775 | 3 | Yes (2) |
| 99790 | 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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