The Power of Information

National Drinking Water Database


Baltimore City Department of Public Works Utilities - Baltimore, MD


Serves 1,600,000 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
109 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)
4 days
Test DaysNumber of days in which this chemical has reported results in the data we received from the State
109 days
Tests ConductedNumber of individual tests done for this contaminant
460 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.44.5 ppb
90.2 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
2007-11-1937 ppb6028 to 50 ppb
2007-11-1842 ppb1042 ppb
2007-11-1638.83 ppb6027 to 47 ppb
2007-11-1440.33 ppb6029 to 55 ppb
2007-09-1952.5 ppb2047 to 58 ppb
2007-09-1854.5 ppb2048 to 61 ppb
2007-09-1758.67 ppb3052 to 64 ppb
2007-09-1458.09 ppb11046 to 81 ppb
2007-07-1957.17 ppb6053 to 61 ppb
2007-07-1844.5 ppb2029 to 60 ppb
2007-07-1740 ppb2025 to 55 ppb
2007-07-1643.33 ppb6029 to 58 ppb
2007-05-1642.67 ppb3041 to 44 ppb
2007-05-1546 ppb2039 to 53 ppb
2007-05-1441.83 ppb6032 to 47 ppb
2007-05-1143.5 ppb6036 to 48 ppb
2007-03-2922.83 ppb4013.5 to 29 ppb
2007-03-2137.33 ppb3025 to 48 ppb
2007-03-2053 ppb2031 to 75 ppb
2007-03-1933.83 ppb6023 to 51 ppb
2007-03-1638.8 ppb5026 to 64 ppb
2007-02-0239 ppb1039 ppb
2007-01-2434 ppb2029 to 39 ppb
2007-01-2332 ppb2029 to 35 ppb
2007-01-2232.5 ppb6022 to 41 ppb
2007-01-1934.2 ppb5029 to 37 ppb
2006-11-2246 ppb1046 ppb
2006-11-2142 ppb3036 to 47 ppb
2006-11-2051.5 ppb6047 to 60 ppb
2006-11-1745.67 ppb6033 to 54 ppb
2006-09-2064.33 ppb3057 to 69 ppb
2006-09-1961 ppb2056 to 66 ppb
2006-09-1846.67 ppb602 to 66 ppb
2006-09-1564.17 ppb6050 to 79 ppb
2006-08-1660.5 ppb2050 to 71 ppb
2006-08-1575.5 ppb2069 to 82 ppb
2006-08-1463.33 ppb6046 to 79 ppb
2006-08-1166.2 ppb5057 to 83 ppb
2006-07-1974.33 ppb3062 to 95 ppb
2006-07-1871.5 ppb2067 to 76 ppb
2006-07-1770.57 ppb7039 to 89 ppb
2006-07-1462.25 ppb4059 to 68 ppb
2006-05-1733 ppb3033 ppb
2006-05-1633.67 ppb3027 to 41 ppb
2006-05-1537.33 ppb6032 to 45 ppb
2006-05-1230.6 ppb5027 to 38 ppb
2006-03-2237.5 ppb2028 to 47 ppb
2006-03-2135 ppb2035 ppb
2006-03-2028.5 ppb6024 to 33 ppb
2006-03-1728.33 ppb6021 to 34 ppb
2006-03-1233 ppb1033 ppb
2006-01-2327.33 ppb6023 to 39 ppb
2006-01-2030 ppb6021 to 37 ppb
2006-01-1826.25 ppb4024 to 29 ppb
2006-01-1739 ppb2026 to 52 ppb
2005-11-1647 ppb3037 to 52 ppb
2005-11-1547 ppb2046 to 48 ppb
2005-11-1436.67 ppb604 to 57 ppb
2005-11-1154 ppb8043 to 68 ppb
2005-09-2146.75 ppb4037 to 56 ppb
2005-09-2047.5 ppb2039 to 56 ppb
2005-09-1947.17 ppb6038 to 57 ppb
2005-09-1646 ppb6032 to 55 ppb
2005-07-2082.75 ppb4069 to 99 ppb
2005-07-1984.5 ppb2075 to 94 ppb
2005-07-1884.83 ppb6068 to 98 ppb
2005-07-1590.2 ppb5069 to 99 ppb
2005-06-2446 ppb5033 to 61 ppb
2005-06-2249.6 ppb5041 to 74 ppb
2005-06-2137 ppb2036 to 38 ppb
2005-06-2041.83 ppb6032 to 54 ppb
2005-03-2324 ppb6020 to 33 ppb
2005-03-2224 ppb7021 to 35 ppb
2005-03-2125.8 ppb5018 to 32 ppb
2005-02-2829.5 ppb4025 to 39 ppb
2005-02-2531.38 ppb8018 to 63 ppb
2005-02-2319.5 ppb4018 to 22 ppb
2005-02-2228.33 ppb3023 to 32 ppb
2005-01-2630.5 ppb6024 to 41 ppb
2005-01-2427 ppb1027 ppb
2005-01-1929.33 ppb3020 to 40 ppb
2005-01-1826 ppb2025 to 27 ppb
2004-11-1846 ppb1046 ppb
2004-11-1746.2 ppb5027 to 62 ppb
2004-11-1650 ppb6029 to 75 ppb
2004-11-1545 ppb6033 to 52 ppb
2004-09-2251 ppb3034 to 64 ppb
2004-09-2158 ppb2048 to 68 ppb
2004-09-2052.17 ppb6039 to 64 ppb
2004-09-1757.75 ppb8041 to 74 ppb
2004-07-2155 ppb4042 to 69 ppb
2004-07-2059.5 ppb2056 to 63 ppb
2004-07-1962.4 ppb5048 to 81 ppb
2004-07-1652.57 ppb7035 to 67 ppb
2004-07-1335.4 ppb4032.3 to 38.5 ppb
2004-07-0954 ppb1054 ppb
2004-05-1937 ppb3029 to 43 ppb
2004-05-1838 ppb3035 to 40 ppb
2004-05-1740.6 ppb5033 to 52 ppb
2004-05-1438.88 ppb8027 to 50 ppb
2004-03-2439 ppb4034 to 51 ppb
2004-03-2342.5 ppb2042 to 43 ppb
2004-03-2240.25 ppb4033 to 53 ppb
2004-03-1938.33 ppb9026 to 58 ppb
2004-01-2826.67 ppb3024 to 29 ppb
2004-01-2725.33 ppb3020 to 30 ppb
2004-01-2631 ppb4023 to 40 ppb
2004-01-2333.6 ppb5020 to 62 ppb
2004-01-0627.05 ppb4026.6 to 27.5 ppb