The Power of Information

National Drinking Water Database


Billerica Water Dept Utilities - Cambridge, MA


Serves 38,981 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
23 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
24 days
Tests ConductedNumber of individual tests done for this contaminant
92 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.34.58 ppb
86.5 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
2009-04-3037.25 ppb4033 to 40 ppb
2009-01-2723.25 ppb4022.2 to 24.1 ppb
2008-10-2247.63 ppb4041.8 to 56.4 ppb
2008-07-2979.15 ppb4064.7 to 94 ppb
2008-04-2920.33 ppb4012.8 to 23.7 ppb
2008-01-2911.68 ppb4010.8 to 12.8 ppb
2007-10-3030.5 ppb4027 to 32 ppb
2007-08-2925 ppb4025 ppb
2007-04-2418.5 ppb4018 to 19 ppb
2007-01-3112 ppb4011 to 13 ppb
2006-11-1544 ppb4042 to 46 ppb
2006-08-2928.75 ppb4025 to 33 ppb
2006-05-3011.25 ppb405 to 26 ppb
2006-04-1986.5 ppb4083 to 90 ppb
2006-04-120.58 ppb100.58 ppb
2006-02-1555 ppb3055 ppb
2005-10-0526 ppb4025 to 28 ppb
2005-09-0739.5 ppb4035 to 42 ppb
2005-05-2639.25 ppb4034.7 to 42.8 ppb
2005-02-1721.63 ppb4019 to 23 ppb
2004-10-2130.5 ppb4029 to 34 ppb
2004-08-2670.5 ppb4066.8 to 75.6 ppb
2004-05-2642.38 ppb4041.6 to 42.7 ppb
2004-02-1128.75 ppb4024 to 31 ppb