The Power of Information

National Drinking Water Database


Scituate Water Division Utilities - Brockton, MA


Serves 27,200 people

Total trihalomethanes (TTHMs)

Total trihalomethanes constitute the sum of four disinfection byproducts: chloroform, bromodichloromethane, dibromochloromethane, and bromoform.
 
This Drinking Water System
Test Days Exceeding Health GuidelinesDefinition of what this is
35 days
Test Days Exceeding Legal LimitsNumber of days in which the samples taken in that day exceed the Maximum Contaminant Level (Depending on the contaminant and its MCL, that may or may not trigger an MCL violation. Some MCLs are based on averages spanning several months to a year)
1 days
Test DaysNumber of days in which this chemical has reported results in the data we received from the State
39 days
Tests ConductedNumber of individual tests done for this contaminant
155 tests

Testing Summary

ContaminantAverage/
Maximum
Result
Health Limit
Exceeded
Legal Limit
Exceeded

Testing History

-Tested      -Detected      -Over Health Guidelines      -Over Legal Limit*
Total trihalomethanes (TTHMs)Total trihalomethanes constitute the sum of four disinfection byproducts: chloroform, bromodichloromethane, dibromochloromethane, and bromoform.37.86 ppb
110.7 ppb
Yes
9.8 ppb
Yes
80 ppb
NOTE: Each dot in the above graph represents one month.
* Water utilities are noted as exceeding the legal limit if any test is above the maximum contaminant level (MCL). Most MCLs are based on annual averages so exceeding the MCL for one test does not necessarily indicate that the system is out of compliance.

Health Based and Legal Limits for Total trihalomethanes (TTHMs)

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

Testing Results

Testing DateAverage
Result
Samples taken that dayNumber of Non-DetectsRange of Results
2009-01-2036.25 ppb4032 to 45 ppb
2008-11-0362 ppb4045 to 81 ppb
2008-10-0641.57 ppb4013.2 to 72 ppb
2008-07-1572.75 ppb4058 to 83 ppb
2008-05-0532 ppb4030 to 34 ppb
2008-04-0717.5 ppb409 to 26 ppb
2008-02-0670 ppb4063 to 84 ppb
2008-01-0735.95 ppb4032.9 to 39 ppb
2007-10-2948.03 ppb4029.6 to 69 ppb
2007-10-0945 ppb4041 to 50 ppb
2007-08-27110.7 ppb40110.7 ppb
2007-07-2363.25 ppb4022 to 79 ppb
2007-05-0724.3 ppb4021.6 to 27 ppb
2007-04-1730.5 ppb4026 to 36 ppb
2007-02-1334.7 ppb4034.7 ppb
2007-02-1234.5 ppb4031 to 39 ppb
2006-10-3151.25 ppb4041 to 62 ppb
2006-10-2429.85 ppb403.7 to 56 ppb
2006-08-3067 ppb4067 ppb
2006-07-0660.75 ppb4048 to 76 ppb
2006-05-2423 ppb4023 ppb
2006-04-0324.25 ppb4020 to 30 ppb
2006-03-089.9 ppb409.9 ppb
2006-01-1026.25 ppb4024 to 28 ppb
2005-10-3119.68 ppb400 to 51 ppb
2005-10-1138.5 ppb4020 to 60 ppb
2005-07-0558 ppb4055 to 61 ppb
2005-05-038 ppb400 to 16 ppb
2005-04-0525.73 ppb4023 to 27 ppb
2005-03-158.63 ppb400 to 25.9 ppb
2005-02-1618.95 ppb4016.9 to 21 ppb
2004-12-207.4 ppb400 to 37 ppb
2004-11-1728 ppb4019 to 34 ppb
2004-09-0762.7 ppb4062.7 ppb
2004-08-2447.9 ppb402.8 to 72.9 ppb
2004-06-1460.6 ppb4060.6 ppb
2004-05-2424.9 ppb400.7 to 45 ppb
2004-03-152.5 ppb302.5 ppb
2004-03-0113.73 ppb409.9 to 16 ppb