This page summarizes EPA Fifth Unregulated Contaminant Monitoring Rule (UCMR 5, 2023–2025) drinking-water monitoring records linked to ZIP codes in Puerto Rico, 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) | 7 (19.4% of state) | 7 (100.0%) — all detections at/above limit by construction | 0.0082 µg/L | 0.022 µg/L |
| PFOS | 0.004 µg/L (MCL) | 24 (66.7% of state) | 24 (100.0%) — all detections at/above limit by construction | 0.0102 µg/L | 0.0467 µg/L |
| PFHxS | 0.01 µg/L (MCL) | 8 (22.2% of state) | 1 (12.5% of detected) | 0.0068 µg/L | 0.0167 µg/L |
| PFBS | 2.0 µg/L (HI reference) | 13 (36.1% of state) | not calculated¹ | 0.0086 µg/L | 0.042 µg/L |
| Lithium | 7.36 µg/L (reference, not a regulatory limit) | 7 (19.4% of state) | 7 (100.0%) at/above reference | 14.9814 µg/L | 25.27 µg/L |
| PFPeA | — (no federal limit) | 16 (44.4% of state) | — | 0.012 µg/L | 0.11 µg/L |
| PFBA | — (no federal limit) | 18 (50.0% of state) | — | 0.0106 µg/L | 0.054 µg/L |
| PFHpA | — (no federal limit) | 1 (2.8% of state) | — | 0.013 µg/L | 0.013 µg/L |
| 6:2 FTS | — (no federal limit) | 3 (8.3% of state) | — | 0.0287 µg/L | 0.049 µg/L |
| PFDA | — (no federal limit) | 5 (13.9% of state) | — | 0.0065 µg/L | 0.0124 µg/L |
36 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 |
|---|---|---|
| 00612 | 2 | Yes (1) |
| 00637 | 1 | No |
| 00638 | 4 | Yes (1) |
| 00646 | 2 | Yes (1) |
| 00647 | 5 | Yes (1) |
| 00653 | 5 | Yes (1) |
| 00660 | 1 | No |
| 00662 | 1 | No |
| 00664 | 1 | No |
| 00669 | 1 | No |
| 00674 | 1 | Yes (1) |
| 00687 | 4 | Yes (1) |
| 00693 | 3 | Yes (1) |
| 00698 | 2 | No |
| 00703 | 2 | Yes (2) |
| 00705 | 2 | Yes (1) |
| 00707 | 2 | Yes (1) |
| 00717 | 4 | Yes (1) |
| 00723 | 4 | Yes (1) |
| 00725 | 2 | Yes (1) |
| 00731 | 7 | Yes (3) |
| 00736 | 3 | Yes (1) |
| 00751 | 5 | Yes (1) |
| 00757 | 4 | Yes (1) |
| 00777 | 3 | Yes (1) |
| 00778 | 3 | Yes (1) |
| 00782 | 1 | No |
| 00783 | 1 | No |
| 00784 | 1 | No |
| 00791 | 2 | Yes (1) |
| 00794 | 2 | Yes (1) |
| 00795 | 7 | Yes (2) |
| 00802 | 3 | Yes (1) |
| 00803 | 3 | Yes (1) |
| 00901 | 6 | Yes (2) |
| 00934 | 2 | 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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