This page summarizes EPA Fifth Unregulated Contaminant Monitoring Rule (UCMR 5, 2023–2025) drinking-water monitoring records linked to ZIP codes in Rhode Island, 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) | 19 (67.9% of state) | 19 (100.0%) — all detections at/above limit by construction | 0.0079 µg/L | 0.016 µg/L |
| PFOS | 0.004 µg/L (MCL) | 8 (28.6% of state) | 8 (100.0%) — all detections at/above limit by construction | 0.0055 µg/L | 0.007 µg/L |
| PFHxS | 0.01 µg/L (MCL) | 4 (14.3% of state) | 0 (0.0% of detected) | 0.0047 µg/L | 0.0086 µg/L |
| PFNA | 0.01 µg/L (MCL) | 1 (3.6% of state) | 0 (0.0% of detected) | 0.007 µg/L | 0.007 µg/L |
| PFBS | 2.0 µg/L (HI reference) | 16 (57.1% of state) | not calculated¹ | 0.0107 µg/L | 0.0368 µg/L |
| Lithium | 7.36 µg/L (reference, not a regulatory limit) | 2 (7.1% of state) | 2 (100.0%) at/above reference | 23.65 µg/L | 35.8 µg/L |
| PFPeA | — (no federal limit) | 21 (75.0% of state) | — | 0.0076 µg/L | 0.0123 µg/L |
| PFBA | — (no federal limit) | 11 (39.3% of state) | — | 0.0073 µg/L | 0.012 µg/L |
| PFHpA | — (no federal limit) | 14 (50.0% of state) | — | 0.0038 µg/L | 0.006 µg/L |
| 6:2 FTS | — (no federal limit) | 11 (39.3% of state) | — | 0.0073 µg/L | 0.0084 µg/L |
28 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 |
|---|---|---|
| 02808 | 6 | Yes (2) |
| 02816 | 5 | Yes (1) |
| 02817 | 5 | Yes (1) |
| 02818 | 5 | Yes (1) |
| 02831 | 5 | Yes (1) |
| 02835 | 1 | No |
| 02840 | 2 | No |
| 02841 | 2 | No |
| 02842 | 2 | No |
| 02852 | 7 | Yes (2) |
| 02860 | 1 | No |
| 02861 | 1 | No |
| 02862 | 1 | No |
| 02863 | 1 | No |
| 02864 | 7 | Yes (2) |
| 02871 | 2 | No |
| 02874 | 5 | Yes (2) |
| 02877 | 5 | Yes (2) |
| 02878 | 1 | Yes (1) |
| 02879 | 4 | Yes (1) |
| 02881 | 8 | Yes (2) |
| 02882 | 3 | Yes (2) |
| 02886 | 5 | Yes (1) |
| 02891 | 6 | Yes (2) |
| 02892 | 4 | Yes (1) |
| 02893 | 5 | Yes (1) |
| 02895 | 4 | Yes (1) |
| 02896 | 4 | 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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