This page summarizes EPA Fifth Unregulated Contaminant Monitoring Rule (UCMR 5, 2023–2025) drinking-water monitoring records linked to ZIP codes in Massachusetts, 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) | 163 (67.9% of state) | 163 (100.0%) — all detections at/above limit by construction | 0.008 µg/L | 0.092 µg/L |
| PFOS | 0.004 µg/L (MCL) | 109 (45.4% of state) | 109 (100.0%) — all detections at/above limit by construction | 0.0085 µg/L | 0.0506 µg/L |
| PFHxS | 0.01 µg/L (MCL) | 47 (19.6% of state) | 5 (10.6% of detected) | 0.0059 µg/L | 0.031 µg/L |
| PFNA | 0.01 µg/L (MCL) | 2 (0.8% of state) | 0 (0.0% of detected) | 0.0048 µg/L | 0.0048 µg/L |
| PFBS | 2.0 µg/L (HI reference) | 118 (49.2% of state) | not calculated¹ | 0.0056 µg/L | 0.0207 µg/L |
| Lithium | 7.36 µg/L (reference, not a regulatory limit) | 27 (11.2% of state) | 27 (100.0%) at/above reference | 18.0341 µg/L | 74.0 µg/L |
| PFPeA | — (no federal limit) | 193 (80.4% of state) | — | 0.0087 µg/L | 0.0594 µg/L |
| PFBA | — (no federal limit) | 102 (42.5% of state) | — | 0.0094 µg/L | 0.025 µg/L |
| PFHpA | — (no federal limit) | 54 (22.5% of state) | — | 0.0055 µg/L | 0.0294 µg/L |
| 6:2 FTS | — (no federal limit) | 3 (1.2% of state) | — | 0.0057 µg/L | 0.0062 µg/L |
240 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 |
|---|---|---|
| 01034 | 1 | No |
| 01038 | 4 | No |
| 01040 | 1 | No |
| 01077 | 1 | No |
| 01082 | 3 | Yes (2) |
| 01085 | 1 | No |
| 01088 | 4 | No |
| 01093 | 1 | No |
| 01201 | 1 | No |
| 01226 | 1 | No |
| 01237 | 1 | No |
| 01240 | 1 | No |
| 01247 | 1 | Yes (1) |
| 01331 | 1 | No |
| 01364 | 1 | No |
| 01373 | 1 | No |
| 01420 | 2 | Yes (1) |
| 01432 | 2 | No |
| 01434 | 2 | No |
| 01436 | 3 | Yes (1) |
| 01438 | 3 | Yes (1) |
| 01450 | 1 | No |
| 01453 | 1 | Yes (1) |
| 01462 | 2 | Yes (1) |
| 01463 | 2 | Yes (2) |
| 01464 | 6 | Yes (1) |
| 01468 | 3 | Yes (1) |
| 01469 | 2 | Yes (1) |
| 01473 | 2 | Yes (1) |
| 01474 | 2 | Yes (1) |
| 01501 | 3 | Yes (2) |
| 01504 | 4 | Yes (1) |
| 01507 | 1 | No |
| 01519 | 4 | Yes (2) |
| 01520 | 4 | Yes (1) |
| 01522 | 4 | Yes (1) |
| 01523 | 4 | Yes (1) |
| 01524 | 2 | No |
| 01527 | 6 | Yes (2) |
| 01536 | 4 | Yes (2) |
| 01537 | 2 | No |
| 01542 | 2 | No |
| 01545 | 4 | Yes (2) |
| 01550 | 1 | No |
| 01560 | 4 | Yes (2) |
| 01564 | 1 | Yes (1) |
| 01569 | 3 | Yes (1) |
| 01570 | 2 | Yes (1) |
| 01581 | 3 | Yes (2) |
| 01583 | 2 | Yes (1) |
| 01586 | 6 | Yes (2) |
| 01602 | 1 | No |
| 01603 | 1 | No |
| 01604 | 1 | No |
| 01605 | 1 | No |
| 01606 | 1 | No |
| 01607 | 6 | Yes (2) |
| 01611 | 2 | No |
| 01612 | 2 | No |
| 01718 | 7 | Yes (2) |
| 01719 | 7 | Yes (2) |
| 01720 | 7 | Yes (2) |
| 01721 | 1 | No |
| 01742 | 3 | Yes (1) |
| 01746 | 4 | Yes (2) |
| 01747 | 3 | Yes (2) |
| 01748 | 4 | Yes (1) |
| 01749 | 1 | No |
| 01754 | 4 | Yes (2) |
| 01757 | 4 | Yes (2) |
| 01760 | 6 | Yes (3) |
| 01773 | 3 | Yes (2) |
| 01775 | 7 | Yes (2) |
| 01776 | 6 | Yes (2) |
| 01778 | 5 | Yes (2) |
| 01801 | 5 | Yes (2) |
| 01803 | 1 | No |
| 01810 | 2 | No |
| 01813 | 5 | Yes (2) |
| 01815 | 5 | Yes (2) |
| 01821 | 4 | Yes (1) |
| 01822 | 4 | Yes (1) |
| 01824 | 4 | Yes (2) |
| 01826 | 3 | Yes (1) |
| 01834 | 3 | Yes (1) |
| 01841 | 2 | Yes (1) |
| 01842 | 1 | No |
| 01843 | 1 | No |
| 01844 | 2 | Yes (1) |
| 01850 | 2 | Yes (1) |
| 01851 | 2 | Yes (1) |
| 01852 | 2 | Yes (1) |
| 01853 | 2 | Yes (1) |
| 01854 | 2 | Yes (1) |
| 01860 | 1 | Yes (1) |
| 01862 | 4 | Yes (1) |
| 01863 | 1 | No |
| 01864 | 2 | No |
| 01865 | 4 | Yes (1) |
| 01866 | 4 | Yes (1) |
| 01876 | 2 | Yes (1) |
| 01879 | 4 | Yes (1) |
| 01880 | 2 | Yes (1) |
| 01886 | 5 | Yes (2) |
| 01887 | 2 | No |
| 01888 | 5 | Yes (2) |
| 01901 | 4 | Yes (1) |
| 01902 | 4 | Yes (1) |
| 01903 | 4 | Yes (1) |
| 01904 | 4 | Yes (1) |
| 01905 | 4 | Yes (1) |
| 01915 | 1 | No |
| 01923 | 5 | Yes (2) |
| 01938 | 5 | Yes (1) |
| 01940 | 4 | Yes (1) |
| 01944 | 5 | Yes (2) |
| 01949 | 6 | Yes (2) |
| 01950 | 2 | Yes (1) |
| 01951 | 2 | Yes (1) |
| 01952 | 3 | Yes (1) |
| 01960 | 4 | Yes (1) |
| 01961 | 4 | Yes (1) |
| 01969 | 6 | Yes (2) |
| 01970 | 1 | No |
| 01971 | 1 | No |
| 01982 | 4 | Yes (2) |
| 01983 | 4 | Yes (2) |
| 01984 | 4 | Yes (2) |
| 01985 | 3 | Yes (1) |
| 02019 | 6 | Yes (2) |
| 02020 | 7 | Yes (2) |
| 02021 | 2 | Yes (1) |
| 02025 | 5 | Yes (2) |
| 02026 | 3 | Yes (2) |
| 02030 | 6 | Yes (3) |
| 02032 | 5 | Yes (2) |
| 02035 | 4 | Yes (2) |
| 02038 | 4 | Yes (2) |
| 02041 | 7 | Yes (2) |
| 02043 | 5 | Yes (2) |
| 02045 | 4 | Yes (1) |
| 02047 | 7 | Yes (2) |
| 02048 | 5 | Yes (2) |
| 02050 | 7 | Yes (2) |
| 02051 | 7 | Yes (2) |
| 02052 | 4 | Yes (2) |
| 02053 | 3 | Yes (1) |
| 02054 | 4 | Yes (2) |
| 02056 | 4 | Yes (2) |
| 02059 | 7 | Yes (2) |
| 02061 | 6 | Yes (2) |
| 02065 | 7 | Yes (2) |
| 02066 | 3 | Yes (2) |
| 02067 | 5 | Yes (3) |
| 02071 | 5 | Yes (2) |
| 02072 | 4 | Yes (2) |
| 02081 | 5 | Yes (2) |
| 02090 | 3 | Yes (2) |
| 02093 | 4 | Yes (2) |
| 02138 | 2 | Yes (1) |
| 02139 | 2 | Yes (1) |
| 02140 | 2 | Yes (1) |
| 02141 | 2 | Yes (1) |
| 02142 | 2 | Yes (1) |
| 02151 | 1 | No |
| 02184 | 4 | Yes (2) |
| 02188 | 1 | No |
| 02189 | 1 | No |
| 02190 | 1 | No |
| 02191 | 1 | No |
| 02324 | 6 | Yes (2) |
| 02330 | 7 | Yes (2) |
| 02332 | 8 | Yes (3) |
| 02333 | 2 | Yes (1) |
| 02334 | 5 | Yes (2) |
| 02338 | 3 | Yes (1) |
| 02339 | 7 | Yes (2) |
| 02341 | 2 | Yes (2) |
| 02343 | 6 | Yes (2) |
| 02346 | 7 | Yes (2) |
| 02347 | 7 | Yes (2) |
| 02350 | 2 | Yes (2) |
| 02351 | 7 | Yes (2) |
| 02356 | 5 | Yes (2) |
| 02359 | 7 | Yes (2) |
| 02360 | 2 | No |
| 02367 | 7 | Yes (2) |
| 02368 | 5 | Yes (2) |
| 02370 | 7 | Yes (2) |
| 02375 | 5 | Yes (2) |
| 02379 | 4 | Yes (1) |
| 02382 | 4 | No |
| 02481 | 5 | Yes (2) |
| 02482 | 6 | Yes (3) |
| 02492 | 2 | Yes (2) |
| 02494 | 2 | Yes (2) |
| 02532 | 3 | Yes (1) |
| 02534 | 3 | Yes (1) |
| 02557 | 1 | No |
| 02558 | 1 | Yes (1) |
| 02559 | 3 | Yes (1) |
| 02562 | 1 | No |
| 02563 | 1 | No |
| 02601 | 2 | No |
| 02630 | 5 | Yes (2) |
| 02631 | 1 | No |
| 02632 | 5 | Yes (2) |
| 02634 | 4 | Yes (1) |
| 02637 | 5 | Yes (2) |
| 02639 | 1 | No |
| 02641 | 1 | No |
| 02648 | 4 | Yes (1) |
| 02649 | 1 | No |
| 02655 | 4 | Yes (1) |
| 02660 | 1 | No |
| 02664 | 4 | No |
| 02668 | 5 | Yes (2) |
| 02670 | 1 | No |
| 02673 | 4 | No |
| 02675 | 7 | Yes (2) |
| 02703 | 4 | Yes (2) |
| 02715 | 3 | Yes (2) |
| 02717 | 1 | No |
| 02719 | 1 | No |
| 02740 | 1 | No |
| 02743 | 1 | No |
| 02744 | 1 | No |
| 02745 | 1 | No |
| 02746 | 1 | No |
| 02747 | 6 | Yes (2) |
| 02748 | 6 | Yes (2) |
| 02760 | 7 | Yes (2) |
| 02762 | 4 | Yes (2) |
| 02764 | 3 | Yes (2) |
| 02766 | 6 | Yes (2) |
| 02767 | 6 | Yes (1) |
| 02768 | 6 | Yes (1) |
| 02770 | 7 | Yes (2) |
| 02771 | 1 | Yes (1) |
| 02777 | 5 | 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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