PFAS in tap water, Middlesex County, Massachusetts
21 of 54 water systems had PFAS-4 above our 0.5 ng/L benchmark at the latest sample. Highest: Natick Water and Sewer Division, 40.8 ng/L. 24 had PFOA or PFOS above the 4 ng/L federal MCL in at least one sample.
54 community water systems · 1,595,808 people served · newest sample May 28, 2026
Water systems in Middlesex County
| Water system | People served | PFAS-4 at the latest sample | Entry points | Latest sample |
|---|---|---|---|---|
| Lowell Regional Water Utility | 120,418 | below the 3 to 4 ng/L reporting limit above the 2029 federal MCL in an earlier sample | 1 | December 13, 2023 |
| Cambridge Water Department | 118,214 | below the 3 to 4 ng/L reporting limit above the 2029 federal MCL in an earlier sample | 1 | June 12, 2024 |
| Newton Water Dept. (MWRA) | 88,931 | below the 3 to 4 ng/L reporting limit | 1 | October 7, 2024 |
| Somerville Water Dept. (MWRA) | 81,045 | below the 3 to 4 ng/L reporting limit | 1 | October 6, 2025 |
| Framingham Water Dept. (MWRA) | 72,362 | below the 3 to 4 ng/L reporting limit | 1 | October 17, 2023 |
| Malden Water Division (MWRA) | 66,263 | below the 3 to 4 ng/L reporting limit | 1 | October 7, 2025 |
| Waltham Water Department | 65,218 | below the 3 to 4 ng/L reporting limit | 1 | December 6, 2023 |
| Medford Water Dept. (MWRA) | 61,700 | below the 3 to 4 ng/L reporting limit | 1 | October 6, 2025 |
| Everett Water Dept. (MWRA) | 49,075 | below the 3 to 4 ng/L reporting limit | 1 | October 7, 2025 |
| Arlington Water Dept. (MWRA) | 46,308 | below the 3 to 4 ng/L reporting limit | 1 | October 17, 2023 |
| Billerica Water Works | 42,119 | 5.5 ng/L above the 2029 federal MCL | 1 | August 7, 2025 |
| Marlborough DPW Water Div. (MWRA) | 41,799 | below the 3 to 4 ng/L reporting limit | 1 | October 30, 2023 |
| Woburn Water Dept. | 40,876 | 15.3 ng/L above the 2029 federal MCL | 2 | October 14, 2025 |
| Natick Water and Sewer Division | 37,006 | 40.8 ng/L above the 2029 federal MCL | 4 | June 11, 2025 |
| Watertown Department of Public Works | 35,985 | below the 3 to 4 ng/L reporting limit | 1 | October 7, 2024 |
| Lexington Water Dept. (MWRA) | 34,074 | below the 3 to 4 ng/L reporting limit | 1 | October 18, 2023 |
| Tewksbury Water Department | 31,342 | 5 ng/L above the 2029 federal MCL | 1 | October 17, 2024 |
| Melrose Water Division (MWRA) | 29,938 | below the 3 to 4 ng/L reporting limit | 1 | October 7, 2025 |
| Chelmsford Water District | 28,750 | below the 3 to 4 ng/L reporting limit above the 2029 federal MCL in an earlier sample | 4 | October 8, 2024 |
| Belmont Water Dept. (MWRA) | 27,442 | below the 3 to 4 ng/L reporting limit | 1 | October 17, 2023 |
| Wakefield Water Dept | 27,090 | 5.5 ng/L above the 2029 federal MCL | 2 | May 28, 2026 |
| Reading Water Department (MWRA) | 26,262 | below the 3 to 4 ng/L reporting limit | 1 | October 21, 2024 |
| Burlington Water Dept | 25,864 | below the 3 to 4 ng/L reporting limit | 2 | October 24, 2024 |
| Dracut Water Supply District | 25,808 | 4.7 ng/L above the 2029 federal MCL | 3 | May 6, 2025 |
| Stoneham Water Dept (MWRA Supply) | 23,244 | below the 3 to 4 ng/L reporting limit | 1 | October 21, 2024 |
| Winchester Water Dept | 22,970 | below the 3 to 4 ng/L reporting limit | 2 | January 7, 2025 |
| Wilmington Water Dept | 21,654 | below the 3 to 4 ng/L reporting limit | 3 | October 1, 2025 |
| Acton Water Supply District | 21,285 | 9.6 ng/L above the 2029 federal MCL | 3 | March 22, 2024 |
| Hudson Water Supply | 20,032 | below the 3 to 4 ng/L reporting limit | 2 | July 16, 2025 |
| Westford Water Department | 18,848 | 8.4 ng/L above the 2029 federal MCL | 2 | October 10, 2023 |
| Ashland Water and Sewer Dept. | 18,832 | below the 3 to 4 ng/L reporting limit | 1 | May 14, 2024 |
| Concord Water Dept | 18,788 | 6 ng/L above the 2029 federal MCL | 6 | August 19, 2024 |
| Sudbury Water District | 18,416 | 9 ng/L above the 2029 federal MCL | 5 | June 6, 2025 |
| North Reading Water Dept. | 16,379 | below the 3 to 4 ng/L reporting limit | 1 | July 1, 2024 |
| Holliston Water Department | 15,139 | 10.9 ng/L above the 2029 federal MCL | 4 | September 10, 2025 |
| Bedford Water Dept. | 14,955 | below the 3 to 4 ng/L reporting limit | 1 | October 17, 2024 |
| Wayland Water Department | 14,096 | 12 ng/L above the 2029 federal MCL | 4 | October 18, 2023 |
| Hopkinton Water Department | 12,680 | 7.2 ng/L above the 2029 federal MCL | 4 | August 18, 2025 |
| Hanscom Afb | 11,789 | below the 3 to 4 ng/L reporting limit | 2 | December 6, 2023 |
| Weston Water Dept. | 11,391 | below the 3 to 4 ng/L reporting limit | 1 | October 18, 2023 |
| Maynard DPW, Water Division | 10,616 | 4.8 ng/L above the 2029 federal MCL | 3 | June 3, 2024 |
| Kenwood Water District | 9,620 | 5.3 ng/L above the 2029 federal MCL | 2 | November 3, 2025 |
| Littleton Water Department | 9,307 | below the 3 to 4 ng/L reporting limit | 1 | December 4, 2024 |
| Pepperell DPW Water Division | 9,217 | 21.4 ng/L above the 2029 federal MCL | 3 | September 19, 2023 |
| Ayer DPW Water Division | 8,479 | below the 3 to 4 ng/L reporting limit | 2 | February 12, 2024 |
| North Chelmsford Water Dist | 7,660 | below the 3 to 4 ng/L reporting limit | 1 | August 1, 2024 |
| Townsend Water Department | 6,832 | 6.5 ng/L above the 2029 federal MCL | 5 | October 7, 2025 |
| Devens Massdevelopment | 6,500 | below the 3 to 4 ng/L reporting limit | 3 | November 7, 2023 |
| Lincoln Water Dept | 5,593 | 9.5 ng/L above the 2029 federal MCL | 2 | December 2, 2025 |
| Groton Water Department | 5,456 | below the 3 to 4 ng/L reporting limit | 2 | December 4, 2024 |
| Tyngsborough Water District | 4,416 | below the 3 to 4 ng/L reporting limit above the 2029 federal MCL in an earlier sample | 2 | November 6, 2023 |
| Shirley Water District | 4,165 | 6 ng/L above the 2029 federal MCL | 3 | January 7, 2026 |
| Mci Shirley | 3,500 | 8.6 ng/L | 1 | December 11, 2023 |
| Haystack Estates | 60 | 5.6 ng/L above the 2029 federal MCL | 1 | November 4, 2025 |
Not sure which one is yours? The systems report their own service areas to EPA. Check your water bill or your utility's Consumer Confidence Report.
Cities and towns
- Acton town/township
- Arlington
- Ashland town/township
- Ayer
- Bedford town/township
- Belmont
- Billerica town/township
- Burlington
- Cambridge
- Chelmsford town/township
- Concord town/township
- Dracut town/township
- Everett
- Framingham
- Groton
- Holliston town/township
- Hopkinton
- Hudson
- Lexington
- Lincoln town/township
- Littleton town/township
- Lowell
- Malden
- Marlborough
- Maynard
- Medford
- Melrose
- Natick town/township
- Newton
- North Reading town/township
- Pepperell
- Reading
- Shirley
- Somerville
- Stoneham
- Sudbury town/township
- Tewksbury town/township
- Townsend
- Tyngsborough town/township
- Wakefield
- Waltham
- Watertown
- Wayland town/township
- Westford town/township
- Weston town/township
- Wilmington
- Winchester
- Woburn
ZIP codes in Middlesex County
Census ZIP code tabulation areas that overlap the county. A ZIP served by one system opens that system's page; a ZIP shared by several systems lists them.
- 01432
- 01434
- 01450
- 01460
- 01463
- 01464
- 01469
- 01474
- 01701
- 01702
- 01718
- 01719
- 01720
- 01721
- 01730
- 01731
- 01742
- 01746
- 01748
- 01749
- 01752
- 01754
- 01760
- 01773
- 01775
- 01776
- 01778
- 01801
- 01803
- 01821
- 01824
- 01826
- 01850
- 01851
- 01852
- 01854
- 01862
- 01863
- 01864
- 01867
- 01876
- 01879
- 01880
- 01886
- 01887
- 01890
- 02138
- 02139
- 02140
- 02141
- 02142
- 02143
- 02144
- 02145
- 02148
- 02149
- 02155
- 02176
- 02180
- 02420
- 02421
- 02451
- 02452
- 02453
- 02458
- 02459
- 02460
- 02461
- 02462
- 02464
- 02465
- 02466
- 02467
- 02468
- 02472
- 02474
- 02476
- 02478
- 02493
How to read these numbers
We compare PFAS-4 (PFOA + PFOS + PFNA + PFHxS) with this site's 0.5 ng/L benchmark, the same line as on the European pages. UCMR 5 reporting limits are 3 to 4 ng/L. So any quantified PFAS-4 compound is above the benchmark, and a clean result reads "below the 3 to 4 ng/L reporting limit", never zero. The US legal limit is the 4 ng/L federal MCL for PFOA and PFOS, which systems must meet from April 26, 2029 ("above the 2029 federal MCL").
EPA: "UCMR 5 results do not indicate compliance or noncompliance with the PFAS drinking water standards". Samples are taken where water enters the distribution system, not at your tap. A system may have changed sources or added treatment since. Source: U.S. Environmental Protection Agency (EPA), Office of Water, PFAS National Primary Drinking Water Regulation (NPDWR). Regulation details retrieved September 19, 2026. Every system page tracks the 2029 compliance date and the proposed rescission of the PFHxS, PFNA, HFPO-DA and Hazard Index limits.
This site is a data project, not an official source. If in doubt, check with your water supplier or local authority.