HAA5 Contamination

HAA5 in Massachusetts Drinking Water

Ranked by average HAA5 concentration (µg/L) · UCMR 4 data (2018–2020) · Data from EPA SDWIS & UCMR

157

Cities Tested

Exceeds Limit

% Exceeds Limit

15.2 µg/L

State Avg

▼ 1% vs national

vs National

263

Health Violations

Analysis

HAA5 in Massachusetts: what the data shows

Massachusetts has 157 cities with HAA5 monitoring data from the EPA's UCMR 4 program (2018–2020). Haloacetic acids (HAA5) form when chlorine-based disinfectants react with natural organic matter in water. The state average is 15.2 µg/L — better than the 15.5 µg/L national average. No cities currently exceed the 60 µg/L EPA MCL. HAA5 is a group of five chlorinated and brominated acetic acids. Long-term exposure above the MCL is associated with increased cancer risk and adverse reproductive outcomes. The EPA classifies total HAA5 as a probable human carcinogen at elevated concentrations. Activated carbon filtration (especially granular or block carbon) is effective at reducing HAA5. Running water through a refrigerator filter or letting it sit in an open pitcher for 30 minutes also helps, as some HAA5 species are volatile. Boiling does not remove disinfection byproducts and may concentrate them.

Comparison

Cities exceeding 60 µg/L EPA MCL

Massachusetts

0 of 157 cities

← ▼ 1% below national rate (better)

National avg

23 of 4420 cities

City Map

HAA5 data across Massachusetts

Each dot is a city with UCMR 4 HAA5 testing data. Cities where average HAA5 exceeded the 60 µg/L EPA MCL are highlighted. Size reflects population served.

Worst Offenders

Top 10 cities by haa5 level in Massachusetts

Highest HAA5 levels (µg/L)

All Cities

All Massachusetts cities ranked by haa5 level

#	City	Level	Exceeds?	Violations	Grade
1	Springfield	52.0 µg/L	No	11	B+
2	East Longmeadow	48.1 µg/L	No	5	A-
3	Agawam	46.7 µg/L	No	8	A-
4	Somerset	43.4 µg/L	No	11	B
5	New Bedford	42.2 µg/L	No	2	A-
6	Chicopee	41.4 µg/L	No	0	A-
7	Worcester	40.8 µg/L	No	3	B
8	Southbridge	40.4 µg/L	No	3	A
9	Ashland	39.2 µg/L	No	7	A-
10	South Hadley	38.5 µg/L	No	16	A-
11	Fitchburg	37.3 µg/L	No	9	B+
12	Pittsfield	36.8 µg/L	No	2	A-
13	Holyoke	35.5 µg/L	No	0	A-
14	Dartmouth	35.5 µg/L	No	16	C+
15	Swansea	34.3 µg/L	No	12	B+
16	Longmeadow	32.8 µg/L	No	18	B
17	Randolph	32.6 µg/L	No	8	B+
18	Beverly	32.3 µg/L	No	0	A-
19	Lawrence	31.6 µg/L	No	3	B+
20	Taunton	28.9 µg/L	No	1	B+
21	Dedham	27.8 µg/L	No	1	B+
22	Brockton	27.6 µg/L	No	5	A-
23	Bellingham	27.1 µg/L	No	21	B-
24	Leominster	26.6 µg/L	No	12	B
25	Braintree	25.8 µg/L	No	1	B
26	Amesbury	25.5 µg/L	No	0	A
27	Abington	24.9 µg/L	No	14	B
28	Salem	24.6 µg/L	No	0	A-
29	Peabody	24.4 µg/L	No	7	B
30	Newburyport	24.2 µg/L	No	3	A-
31	Holbrook	24.0 µg/L	No	15	B+
32	Clinton	23.7 µg/L	No	17	A-
33	Whitman	23.4 µg/L	No	5	A-
34	Amherst	22.7 µg/L	No	6	A-
35	Walpole	22.6 µg/L	No	6	A-
36	Attleboro	22.5 µg/L	No	3	A-
37	Gloucester	22.4 µg/L	No	4	A
38	Hingham	21.9 µg/L	No	2	C+
39	Hudson	21.5 µg/L	No	7	F
40	Westford	21.2 µg/L	No	9	B
41	North Adams	21.2 µg/L	No	5	B
42	Methuen	20.3 µg/L	No	1	A
43	Fall River	20.0 µg/L	No	11	B-
44	Dighton	19.1 µg/L	No	7	D+
45	Tewksbury	18.8 µg/L	No	3	B
46	Holden	18.6 µg/L	No	18	B
47	Danvers	18.4 µg/L	No	5	B+
48	Wakefield	17.0 µg/L	No	10	B+
49	Sudbury	16.6 µg/L	No	10	B-
50	Dalton	16.4 µg/L	No	6	A
51	Burlington	16.1 µg/L	No	7	B+
52	Mansfield	15.9 µg/L	No	6	A-
53	Greenfield	15.7 µg/L	No	3	A-
54	Chelsea	15.6 µg/L	No	17	A-
55	Gardner	15.5 µg/L	No	7	A-
56	Boston	15.3 µg/L	No	5	B
57	Lincoln	14.8 µg/L	No	8	B+
58	Stoughton	14.7 µg/L	No	13	B
59	Saugus	14.6 µg/L	No	10	A-
60	Malden	14.4 µg/L	No	20	B-
61	Brookline	14.4 µg/L	No	6	A-
62	Winthrop	14.4 µg/L	No	8	B+
63	Lexington	14.3 µg/L	No	7	B+
64	Hanover	14.3 µg/L	No	12	C-
65	Marlborough	14.2 µg/L	No	5	A-
66	Everett	14.0 µg/L	No	8	B+
67	Milford	14.0 µg/L	No	15	F
68	Norton	13.9 µg/L	No	10	B+
69	Milton	13.9 µg/L	No	6	B+
70	Stoneham	13.8 µg/L	No	15	A-
71	Dracut	13.8 µg/L	No	5	B
72	Maynard	13.5 µg/L	No	8	B-
73	Sandwich	13.5 µg/L	No	13	A
74	Haverhill	13.5 µg/L	No	1	C
75	Medford	13.3 µg/L	No	9	C
76	Watertown	13.2 µg/L	No	5	A-
77	Marblehead	13.1 µg/L	No	7	A-
78	Lynn	13.0 µg/L	No	5	A-
79	Weston	12.8 µg/L	No	16	A-
80	Swampscott	12.8 µg/L	No	9	A-
81	Somerville	12.7 µg/L	No	12	B+
82	Foxborough	12.6 µg/L	No	11	A-
83	Newton	12.6 µg/L	No	8	B
84	Norwood	12.1 µg/L	No	8	A-
85	Arlington	12.0 µg/L	No	4	A-
86	Belmont	12.0 µg/L	No	5	B+
87	Revere	11.9 µg/L	No	13	B+
88	Framingham	11.7 µg/L	No	4	A-
89	Salisbury	11.6 µg/L	No	0	A-
90	Quincy	11.6 µg/L	No	6	A-
91	Weymouth	11.6 µg/L	No	6	A
92	Billerica	11.5 µg/L	No	7	B+
93	Westfield	11.3 µg/L	No	7	B+
94	Scituate	11.2 µg/L	No	10	C
95	Seekonk	11.1 µg/L	No	7	A-
96	Westborough	11.1 µg/L	No	13	D
97	Lowell	10.9 µg/L	No	5	B+
98	North Reading	10.7 µg/L	No	9	A-
99	Wellesley	10.7 µg/L	No	20	B
100	Northborough	10.6 µg/L	No	10	B
101	Waltham	10.6 µg/L	No	11	A-
102	Norwell	10.5 µg/L	No	5	B+
103	Melrose	10.5 µg/L	No	16	B
104	North Andover	10.2 µg/L	No	5	A
105	Winchester	10.0 µg/L	No	5	C-
106	Reading	9.5 µg/L	No	1	A-
107	Cambridge	9.5 µg/L	No	2	B+
108	Ipswich	9.2 µg/L	No	8	B
109	Holliston	9.1 µg/L	No	11	C-
110	Woburn	9.1 µg/L	No	5	B+
111	Grafton	9.1 µg/L	No	25	F
112	Needham	8.7 µg/L	No	4	A-
113	Concord	8.3 µg/L	No	4	B+
114	Chelmsford	8.1 µg/L	No	1	B-
115	Canton	8.0 µg/L	No	11	A-
116	Wilmington	7.4 µg/L	No	5	A-
117	Natick	7.2 µg/L	No	3	B+
118	Bridgewater	7.0 µg/L	No	5	C+
119	Middleborough	6.8 µg/L	No	16	B
120	Acton	6.8 µg/L	No	28	F
121	Athol	6.7 µg/L	No	3	A
122	Shrewsbury	6.7 µg/L	No	3	B+
123	Northampton	6.7 µg/L	No	5	A-
124	North Attleborough	6.6 µg/L	No	15	F
125	Webster	6.5 µg/L	No	19	B
126	Wayland	6.5 µg/L	No	11	B+
127	East Bridgewater	5.8 µg/L	No	6	B+
128	Easton	5.6 µg/L	No	3	A-
129	Auburn	5.2 µg/L	No	16	D+
130	Bedford	5.1 µg/L	No	35	B+
131	Upton	4.8 µg/L	No	9	C
132	Uxbridge	4.6 µg/L	No	2	A-
133	Norfolk	4.6 µg/L	No	12	F
134	Andover	4.5 µg/L	No	2	B+
135	Medway	4.5 µg/L	No	14	B-
136	Falmouth	3.9 µg/L	No	23	B
137	Harwich	3.6 µg/L	No	3	A+
138	Orleans	3.3 µg/L	No	3	B
139	Chatham	3.2 µg/L	No	19	A
140	Medfield	3.0 µg/L	No	14	B+
141	Franklin	2.1 µg/L	No	11	B+
142	Bourne	1.8 µg/L	No	16	B-
143	Wareham	1.8 µg/L	No	22	B
144	Ware	1.8 µg/L	No	11	B
145	Sharon	1.5 µg/L	No	5	D+
146	Dennis	1.4 µg/L	No	5	A
147	Provincetown	1.3 µg/L	No	5	A
148	Duxbury	1.1 µg/L	No	4	B+
149	Barnstable	0.9 µg/L	No	34	D+
150	Kingston	0.9 µg/L	No	12	C
151	Plymouth	0.9 µg/L	No	20	F
152	Brewster	0.7 µg/L	No	1	B+
153	Oak Bluffs	0.6 µg/L	No	18	B+
154	West Springfield	0.3 µg/L	No	7	A
155	Marshfield	0.0 µg/L	No	9	B-
156	Pembroke	0.0 µg/L	No	16	A
157	Easthampton	0.0 µg/L	No	8	A

FAQ

Frequently asked questions about haa5 in Massachusetts

What is HAA5 and why does it appear in Massachusetts tap water?

HAA5 (haloacetic acids) are disinfection byproducts that form when chlorine reacts with naturally occurring organic matter in source water. They are a normal byproduct of the disinfection process that makes water safe to drink. No cities in Massachusetts currently exceed the 60 µg/L EPA MCL. The state average is 15.2 µg/L.

How can I reduce HAA5 exposure from Massachusetts drinking water?

Activated carbon filters (granular or block) effectively reduce HAA5. Refrigerator filters and under-sink carbon systems are convenient options. Unlike lead or PFAS, HAA5 levels can also be reduced by letting water stand in an open container, as some species evaporate. Boiling does NOT remove HAA5 and can concentrate them by reducing water volume.

Which Massachusetts cities have the highest HAA5 levels?

The cities with the highest average HAA5 concentrations in Massachusetts are: Springfield (52.0 µg/L), East Longmeadow (48.1 µg/L), Agawam (46.7 µg/L), Somerset (43.4 µg/L), New Bedford (42.2 µg/L). Note: this data is from UCMR 4 testing (2018–2020) and may not reflect current levels.

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