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National Drinking Water Database


Total trihalomethanes (TTHMs) in Massachusetts


Total trihalomethanes constitute the sum of four disinfection byproducts: chloroform, bromodichloromethane, dibromochloromethane, and bromoform. [read more]

The Most Polluted Communities in Massachusetts

311 water utilities reported detecting Total trihalomethanes (TTHMs) in tap water since 2004, according to EWG's analysis of water quality data supplied by state water agencies

Ranked by highest average Total trihalomethanes (TTHMs) level

RankSystem Population Served Positive test results of total reported tests Average Level
(Range)
1Leino Park Water District
Westminster, MA
8018 of 1888.48 ppb
(44.8 to 126.3 ppb)
2Westboro State Hospital
Westborough, MA
1,3098 of 879.39 ppb
(6.52 to 119 ppb)
3Holmes Park Water District
Westminster, MA
11217 of 1776.32 ppb
(52.5 to 130 ppb)
4Westminster Department of Public Works
Westminster, MA
4,81025 of 2575.41 ppb
(33.3 to 129.6 ppb)
5East Longmeadow Dpw Water Dept
East Longmeadow, MA
14,70720 of 2070.97 ppb
(42.4 to 91.1 ppb)
6Chester Water Dept
Chester, MA
75023 of 2370.63 ppb
(9.31 to 125.23 ppb)
7Framingham Water Dept. (Mwra)
Framingham, MA
66,9107 of 768.78 ppb
(54.41 to 89.8 ppb)
8Agawam Water Dept
Agawam, MA
28,14420 of 2068.25 ppb
(39.38 to 109.35 ppb)
9Cohasset Water Dept
MA
6,52131 of 3167.57 ppb
(5.4 to 131 ppb)
10Woodland Water District
Auburn, MA
42516 of 1666.86 ppb
(45 to 93 ppb)

Health Based Limits for Total trihalomethanes (TTHMs)

StandardDescriptionLevel
One in one million (10-6) Cancer RiskThe concentration of a chemical in drinking water corresponding to an excess estimated lifetime cancer risk of 1 in 1,000,000. Source: U.S. Environmental Protection Agency.9.8 ppb
EPA Human Health Water Quality CriteriaWater quality criteria set by the US EPA provide guidance for states and tribes authorized to establish water quality standards under the Clean Water Act (CWA) to protect human health. These are non-enforceable standards based upon exposure by both drinking water and the contribution of water contamination to other consumed foods. Source: U.S. Environmental Protection Agency.11.5 ppb
Maximum Contaminant Limit (MCL)The enforceable standard which defines the highest level of a contaminant that is allowed in drinking water. MCLs are set as close to health-based limits (Maximum Contaminant Level Goals, or MCLGs) as feasible using the best available analytical and treatment technologies and taking cost into consideration. Source: U.S. Environmental Protection Agency.80 ppb
Lifetime health-based limit, non-cancer riskConcentration of a chemical in drinking water that is not expected to cause any adverse, noncarcinogenic health effects for a lifetime of exposure. The Lifetime health-based limit (or Health Advisory, HA) is based on exposure for a a 70-kg adult consuming 2 liters of water per day. Source: U.S. Environmental Protection Agency.130 ppb
One in ten thousand (10-4) Cancer RiskThe concentration of a chemical in drinking water corresponding to an excess estimated lifetime cancer risk of 1 in 10,000. Source: U.S. Environmental Protection Agency.980 ppb
Drinking Water Equivalent LevelA lifetime exposure concentration protective of adverse, noncarcinogenic health effects, that assumes all of the exposure to a contaminant is from drinking water. Source: U.S. Environmental Protection Agency.1835 ppb
Children's health-based limit for 10-day exposureConcentration of a chemical in drinking water that is not expected to cause any adverse, noncarcinogenic effects for up to ten days of exposure. The Ten-Day health-based limit (or Health Advisory, HA) is typically set to protect a 10-kg child consuming 1 liter of water per day. Source: U.S. Environmental Protection Agency.4860 ppb
Children's health-based limit for 1-day exposureConcentration of a chemical in drinking water that is not expected to cause any adverse, noncarcinogenic health effects for up to one day of exposure. The One-Day health-based limit (or Health Advisory, HA) is typically set to protect a 10-kg child consuming 1 liter of water per day. Source: U.S. Environmental Protection Agency.10600 ppb

Violation Summary for Total trihalomethanes (TTHMs) in Massachusetts

Data from the U.S. Environmental Protection Agency includes the following violations of federal standards in Massachusetts since 2004

Violation TypeNumber of Violations
Over maximum contaminant level, Average31
Monitoring and Reporting Disinfection Byproduct Rule28
Failure to monitor regularly4