The Power of Information

National Drinking Water Database


Philadelphia Water Department Utilities - Philadelphia, PA


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
44 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)
5 days
Test DaysNumber of days in which this chemical has reported results in the data we received from the State
44 days
Tests ConductedNumber of individual tests done for this contaminant
540 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.44.62 ppb
90 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
2009-03-1127.75 ppb12019 to 35 ppb
2009-02-1125.75 ppb12016 to 33 ppb
2009-01-1419.92 ppb12017 to 23 ppb
2008-12-1026.83 ppb12018 to 37 ppb
2008-11-1248.17 ppb12030 to 59 ppb
2008-10-0869.17 ppb12039 to 99 ppb
2008-09-1781.33 ppb6074 to 90 ppb
2008-08-1390 ppb12055 to 118 ppb
2008-07-0985.92 ppb12060 to 99 ppb
2008-06-1160.33 ppb12043 to 86 ppb
2008-05-1440.58 ppb12022 to 54 ppb
2008-04-0921.67 ppb12015 to 27 ppb
2008-03-1223.08 ppb12019 to 27 ppb
2008-02-1319.75 ppb12014 to 22 ppb
2008-01-0922.33 ppb12019 to 25 ppb
2007-12-1227.17 ppb12021 to 35 ppb
2007-11-1439.58 ppb12034 to 44 ppb
2007-10-1068.42 ppb12050 to 80 ppb
2007-09-1376.5 ppb4074 to 80 ppb
2007-09-1267.88 ppb8054 to 82 ppb
2007-08-0866.83 ppb12049 to 78 ppb
2007-07-1164.42 ppb12047 to 82 ppb
2007-06-1360.08 ppb12043 to 69 ppb
2007-05-0934.75 ppb12031 to 38 ppb
2007-04-1122.67 ppb12013 to 26 ppb
2007-03-1421.4 ppb15020 to 23 ppb
2007-02-2113.5 ppb12012 to 16 ppb
2007-01-1021.75 ppb12018 to 25 ppb
2006-12-1315.33 ppb15012 to 18 ppb
2006-11-0833 ppb12028 to 39 ppb
2006-10-1144.83 ppb12041 to 47 ppb
2006-09-1350.58 ppb12046 to 57 ppb
2006-08-0977.75 ppb12065 to 89 ppb
2006-07-1980.5 ppb12058 to 99 ppb
2006-05-1542 ppb12036 to 50 ppb
2006-01-1825.25 ppb12022 to 28 ppb
2005-11-0246 ppb12033 to 58 ppb
2005-07-2181.67 ppb12067 to 94 ppb
2005-04-1333.33 ppb12028 to 40 ppb
2005-01-1922.83 ppb12016 to 28 ppb
2004-10-2735.08 ppb24030 to 39 ppb
2004-07-2169.17 ppb12044 to 84 ppb
2004-04-2844.33 ppb12039 to 56 ppb
2004-01-2914 ppb24010 to 18 ppb