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National Drinking Water Database


Total trihalomethanes (TTHMs) in Vermont


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

The Most Polluted Communities in Vermont

232 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)
1Springfield Water Dept
Springfield, VT
9,8001 of 1110.21 ppb
(110.21 ppb)
2North Hero Water System
North Hero, VT
1,80014 of 1481.71 ppb
(40 to 163 ppb)
3Proctor Water Dept
Proctor, VT
2,20012 of 1279.63 ppb
(28.8 to 211 ppb)
4Chapel Mhp
Bennington, VT
765 of 574.12 ppb
(30 to 104 ppb)
5St Johnsbury Water System
St Johnsbury, VT
5,00016 of 1665.48 ppb
(3.3 to 117 ppb)
6Patterson Mhp
Duxbury, VT
392 of 265 ppb
(60 to 70 ppb)
7Gore Road Mhp
Bennington, VT
10011 of 1164.36 ppb
(20 to 140 ppb)
8West Road Mhp
Bennington, VT
10511 of 1164.09 ppb
(20 to 110 ppb)
9Rutland Town Fire District 8
Rutland Town, VT
453 of 363.33 ppb
(60 to 70 ppb)
10Grand Isle Consolidated Water District
Grand Isle, VT
1,36514 of 1459.8 ppb
(43.35 to 79.4 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 Vermont

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

Violation TypeNumber of Violations
Monitoring and Reporting Disinfection Byproduct Rule67
Over maximum contaminant level, Average50
Failure to monitor regularly10
Over maximum contaminant level, Single Sample1