Chromium-6 Contamination

Chromium-6 in Massachusetts Drinking Water

Ranked by max chromium-6 detected (µg/L) · UCMR 3 data (2013–2015) · Data from EPA SDWIS & UCMR

147

Cities Tested

147

Detected

100%

% Detected

0.48 µg/L

State Avg

▼ 0% vs national

vs National

263

Health Violations

Analysis

Chromium-6 in Massachusetts: what the data shows

Massachusetts has 147 cities with chromium-6 data from the EPA's UCMR 3 program (2013–2015). Hexavalent chromium (Cr VI) was detected in 147 of those cities. There is currently no federal MCL for chromium-6 — California's 10 µg/L limit is used as a reference. The state average max detected level is 0.48 µg/L. Chromium-6 occurs naturally in some groundwater aquifers but also from industrial discharge, particularly from steel processing, chrome plating, and leather tanning. It is distinct from trivalent chromium (Cr III), which is an essential nutrient at low doses. The National Toxicology Program and IARC classify chromium-6 as a carcinogen via inhalation; the evidence for drinking water carcinogenicity is strong but regulatory action at the federal level remains pending as of 2026. Reverse osmosis systems effectively remove chromium-6 to near-undetectable levels.

Comparison

Cities exceeding No federal MCL (CA: 10 µg/L)

Massachusetts

100%

147 of 147 cities

← = Exactly at national rate

National avg

100%

4005 of 4005 cities

City Map

Chromium-6 data across Massachusetts

Each dot is a city with UCMR 3 chromium-6 data. Detected cities are shown; there is no federal MCL — California's 10 µg/L limit is used as a reference. Size reflects population served.

Worst Offenders

Top 10 cities by chromium-6 level in Massachusetts

Highest Chromium-6 levels (µg/L)

All Cities

All Massachusetts cities ranked by chromium-6 level

#	City	Level	Detected?	Violations	Grade
1	Harwich	20.00 µg/L	Detected	3	A+
2	Danvers	4.40 µg/L	Detected	5	B+
3	Shrewsbury	4.10 µg/L	Detected	3	B+
4	Westfield	2.20 µg/L	Detected	7	B+
5	Hanover	1.80 µg/L	Detected	12	C-
6	Rowley	1.70 µg/L	Detected	10	B
7	Abington	1.60 µg/L	Detected	14	B
8	Oak Bluffs	1.19 µg/L	Detected	18	B+
9	Easthampton	0.98 µg/L	Detected	8	A
10	Fairhaven	0.96 µg/L	Detected	9	A
11	Wilmington	0.90 µg/L	Detected	5	A-
12	Norwell	0.86 µg/L	Detected	5	B+
13	Northampton	0.85 µg/L	Detected	5	A-
14	Stoughton	0.80 µg/L	Detected	13	B
15	Acton	0.77 µg/L	Detected	28	F
16	Marshfield	0.71 µg/L	Detected	9	B-
17	Hingham	0.68 µg/L	Detected	2	C+
18	Holden	0.66 µg/L	Detected	18	B
19	Hatfield	0.64 µg/L	Detected	3	A-
20	Yarmouth	0.59 µg/L	Detected	7	A-
21	West Springfield	0.57 µg/L	Detected	7	A
22	Barnstable	0.56 µg/L	Detected	34	D+
23	Provincetown	0.52 µg/L	Detected	5	A
24	South Hadley	0.51 µg/L	Detected	16	A-
25	Billerica	0.51 µg/L	Detected	7	B+
26	Sandwich	0.49 µg/L	Detected	13	A
27	Sharon	0.49 µg/L	Detected	5	D+
28	Nantucket	0.44 µg/L	Detected	12	D
29	Duxbury	0.44 µg/L	Detected	4	B+
30	Topsfield	0.43 µg/L	Detected	8	B+
31	Holliston	0.42 µg/L	Detected	11	C-
32	Medfield	0.42 µg/L	Detected	14	B+
33	Edgartown	0.41 µg/L	Detected	6	A
34	Worcester	0.40 µg/L	Detected	3	B
35	Franklin	0.39 µg/L	Detected	11	B+
36	Bellingham	0.39 µg/L	Detected	21	B-
37	Orleans	0.38 µg/L	Detected	3	B
38	Scituate	0.37 µg/L	Detected	10	C
39	Medway	0.36 µg/L	Detected	14	B-
40	Mashpee	0.35 µg/L	Detected	4	B
41	Bridgewater	0.34 µg/L	Detected	5	C+
42	Mansfield	0.33 µg/L	Detected	6	A-
43	Plymouth	0.32 µg/L	Detected	20	F
44	Grafton	0.32 µg/L	Detected	25	F
45	Easton	0.30 µg/L	Detected	3	A-
46	Bourne	0.29 µg/L	Detected	16	B-
47	Brewster	0.28 µg/L	Detected	1	B+
48	Natick	0.26 µg/L	Detected	3	B+
49	Tewksbury	0.26 µg/L	Detected	3	B
50	Kingston	0.26 µg/L	Detected	12	C
51	Mattapoisett	0.25 µg/L	Detected	9	A
52	Wareham	0.25 µg/L	Detected	22	B
53	Sudbury	0.25 µg/L	Detected	10	B-
54	Dennis	0.24 µg/L	Detected	5	A
55	Dedham	0.24 µg/L	Detected	1	B+
56	Dartmouth	0.24 µg/L	Detected	16	C+
57	Walpole	0.24 µg/L	Detected	6	A-
58	Newburyport	0.24 µg/L	Detected	3	A-
59	Amherst	0.23 µg/L	Detected	6	A-
60	Falmouth	0.22 µg/L	Detected	23	B
61	Winchester	0.22 µg/L	Detected	5	C-
62	Canton	0.22 µg/L	Detected	11	A-
63	Middleborough	0.22 µg/L	Detected	16	B
64	Chatham	0.20 µg/L	Detected	19	A
65	Salisbury	0.20 µg/L	Detected	0	A-
66	Wayland	0.20 µg/L	Detected	11	B+
67	Randolph	0.19 µg/L	Detected	8	B+
68	Norton	0.19 µg/L	Detected	10	B+
69	Haverhill	0.18 µg/L	Detected	1	C
70	Weymouth	0.18 µg/L	Detected	6	A
71	Leominster	0.18 µg/L	Detected	12	B
72	Westborough	0.18 µg/L	Detected	13	D
73	Westford	0.18 µg/L	Detected	9	B
74	Ipswich	0.18 µg/L	Detected	8	B
75	North Adams	0.18 µg/L	Detected	5	B
76	Concord	0.17 µg/L	Detected	4	B+
77	Foxborough	0.17 µg/L	Detected	11	A-
78	Tisbury	0.17 µg/L	Detected	9	B+
79	Chelmsford	0.16 µg/L	Detected	1	B-
80	Pembroke	0.16 µg/L	Detected	16	A
81	East Bridgewater	0.16 µg/L	Detected	6	B+
82	Plainville	0.16 µg/L	Detected	9	B
83	Ashland	0.15 µg/L	Detected	7	A-
84	Swansea	0.15 µg/L	Detected	12	B+
85	Amesbury	0.15 µg/L	Detected	0	A
86	Lawrence	0.14 µg/L	Detected	3	B+
87	Methuen	0.14 µg/L	Detected	1	A
88	Holyoke	0.14 µg/L	Detected	0	A-
89	Needham	0.13 µg/L	Detected	4	A-
90	Lynn	0.13 µg/L	Detected	5	A-
91	Brookline	0.13 µg/L	Detected	6	A-
92	Peabody	0.13 µg/L	Detected	7	B
93	Whitman	0.13 µg/L	Detected	5	A-
94	Gloucester	0.13 µg/L	Detected	4	A
95	Attleboro	0.12 µg/L	Detected	3	A-
96	Beverly	0.12 µg/L	Detected	0	A-
97	Wellesley	0.12 µg/L	Detected	20	B
98	Southbridge	0.12 µg/L	Detected	3	A
99	North Attleborough	0.11 µg/L	Detected	15	F
100	Greenfield	0.11 µg/L	Detected	3	A-
101	Seekonk	0.11 µg/L	Detected	7	A-
102	North Reading	0.10 µg/L	Detected	9	A-
103	Holbrook	0.10 µg/L	Detected	15	B+
104	Marlborough	0.10 µg/L	Detected	5	A-
105	Milford	0.10 µg/L	Detected	15	F
106	Webster	0.10 µg/L	Detected	19	B
107	Arlington	0.09 µg/L	Detected	4	A-
108	Hadley	0.09 µg/L	Detected	7	A
109	Taunton	0.09 µg/L	Detected	1	B+
110	Salem	0.09 µg/L	Detected	0	A-
111	Uxbridge	0.09 µg/L	Detected	2	A-
112	Framingham	0.09 µg/L	Detected	4	A-
113	Clinton	0.08 µg/L	Detected	17	A-
114	Andover	0.08 µg/L	Detected	2	B+
115	North Andover	0.08 µg/L	Detected	5	A
116	Hudson	0.08 µg/L	Detected	7	F
117	Somerset	0.08 µg/L	Detected	11	B
118	Cambridge	0.07 µg/L	Detected	2	B+
119	Pittsfield	0.07 µg/L	Detected	2	A-
120	Burlington	0.07 µg/L	Detected	7	B+
121	Lowell	0.07 µg/L	Detected	5	B+
122	Springfield	0.06 µg/L	Detected	11	B+
123	Fitchburg	0.06 µg/L	Detected	9	B+
124	Dighton	0.06 µg/L	Detected	7	D+
125	Dracut	0.06 µg/L	Detected	5	B
126	Longmeadow	0.06 µg/L	Detected	18	B
127	Maynard	0.06 µg/L	Detected	8	B-
128	Revere	0.06 µg/L	Detected	13	B+
129	New Bedford	0.06 µg/L	Detected	2	A-
130	Winthrop	0.06 µg/L	Detected	8	B+
131	Melrose	0.05 µg/L	Detected	16	B
132	Saugus	0.05 µg/L	Detected	10	A-
133	Stoneham	0.05 µg/L	Detected	15	A-
134	Marblehead	0.05 µg/L	Detected	7	A-
135	Reading	0.05 µg/L	Detected	1	A-
136	Malden	0.05 µg/L	Detected	20	B-
137	Woburn	0.05 µg/L	Detected	5	B+
138	Chelsea	0.05 µg/L	Detected	17	A-
139	Swampscott	0.04 µg/L	Detected	9	A-
140	Brockton	0.04 µg/L	Detected	5	A-
141	Agawam	0.04 µg/L	Detected	8	A-
142	Bedford	0.04 µg/L	Detected	35	B+
143	Somerville	0.04 µg/L	Detected	12	B+
144	East Longmeadow	0.04 µg/L	Detected	5	A-
145	Lexington	0.03 µg/L	Detected	7	B+
146	Wakefield	0.03 µg/L	Detected	10	B+
147	Belmont	0.03 µg/L	Detected	5	B+

FAQ

Frequently asked questions about chromium-6 in Massachusetts

Is chromium-6 in Massachusetts tap water dangerous?

Chromium-6 (hexavalent chromium) is a potential human carcinogen. There is currently no federal MCL — California's 10 µg/L limit is the most protective US standard. 147 cities in Massachusetts had detectable chromium-6 in UCMR 3 testing (2013–2015). Reverse osmosis is the most effective removal method.

Where does chromium-6 come from in Massachusetts water?

Chromium-6 enters water supplies from two main sources: natural weathering of chromium-containing rock formations (especially in the Southwest and parts of the Midwest) and industrial discharge from steel mills, chrome plating, and coal ash sites. Groundwater systems are more commonly affected by natural sources, while surface water systems near industrial areas face pollution-related risks.

How can I filter chromium-6 from my water in Massachusetts?

Reverse osmosis (RO) systems are the most effective, removing over 95% of chromium-6. Some high-quality activated alumina or anion exchange filters also provide significant reduction. Standard carbon filters and pitcher filters are generally NOT effective against chromium-6. Look for filters certified by NSF International against NSF/ANSI 58 (for RO systems).

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