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National Drinking Water Database


Chloroform in Montana


Chloroform is a disinfection byproduct from the trihalomethane (THM) family, and is formed when chlorine, chloramines or other disinfectants react with organic and inorganic matter in water. [read more]

The Most Polluted Communities in Montana

183 water utilities reported detecting Chloroform in tap water since 2004, according to EWG's analysis of water quality data supplied by state water agencies

Ranked by highest average Chloroform level

RankSystem Population Served Positive test results of total reported tests Average Level
(Range)
1Brady County Water and Sewer District
Brady, MT
22510 of 1096.4 ppb
(5 to 146 ppb)
2North Havre County Water Dist
Havre, MT
9011 of 1172.59 ppb
(28 to 114 ppb)
3Town of Medicine Lake
Medicine Lake, MT
3571 of 163 ppb
(63 ppb)
4Cut Bank North Water District
Santa Rita, MT
4781 of 145.9 ppb
(45.9 ppb)
5Seeley Lake Water District
Seeley Lake, MT
1,57514 of 1442.79 ppb
(22 to 98 ppb)
6Malmstrom Air Force Base
Malmstrom Afb, MT
8,0005 of 542.23 ppb
(26 to 65.6 ppb)
7Town of Philipsburg
Philipsburg, MT
92513 of 1341.62 ppb
(0.03 to 69.9 ppb)
8Fort Peck Rural County Water District
Fort Peck, MT
6635 of 541.1 ppb
(37.5 to 46 ppb)
9Town of Froid
Froid, MT
1951 of 141 ppb
(41 ppb)
10City of Havre
Havre, MT
9,80016 of 1640.48 ppb
(10 to 81 ppb)

Health Based Limits for Chloroform

StandardDescriptionLevel
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.5.7 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.35 ppb
Maximum Contaminant Limit Goal (MCLG)A non-enforceable health goal that is set at a level at which no known or anticipated adverse effect on the health of persons occurs and which allows an adequate margin of safety. Source: U.S. Environmental Protection Agency.70 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.70 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
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.4000 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.4000 ppb

Violation Summary for Chloroform in Montana

There are no violations reported for this contaminant in Montana