The Power of Information

National Drinking Water Database


City of Houston Public Works Utilities - Houston, TX


Serves 2,700,000 people

Chloroform

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.
 
This Drinking Water System
Test Days Exceeding Health GuidelinesDefinition of what this is
37 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)
0 days
Test DaysNumber of days in which this chemical has reported results in the data we received from the State
51 days
Tests ConductedNumber of individual tests done for this contaminant
588 tests

Testing Summary

ContaminantAverage/
Maximum
Result
Health Limit
Exceeded
Legal Limit
Exceeded

Testing History

-Tested      -Detected      -Over Health Guidelines      -Over Legal Limit*
ChloroformChloroform 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.11.29 ppb
36.58 ppb
Yes
5.7 ppb
No
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 Chloroform

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

Testing Results

Testing DateAverage
Result
Samples taken that dayNumber of Non-DetectsRange of Results
2007-11-0110.49 ppb1510 to 16.4 ppb
2007-10-3111.88 ppb1720 to 16.4 ppb
2007-09-208.95 ppb1350 to 29.7 ppb
2007-09-1936.58 ppb1010 to 161 ppb
2007-08-0925.4 ppb209.2 to 41.6 ppb
2007-07-260 ppb110 ppb
2007-07-2525.18 ppb1410 to 39.5 ppb
2007-06-0725.22 ppb15013.4 to 37.5 ppb
2007-06-0626.15 ppb1720 to 43.5 ppb
2007-04-1110.74 ppb1370 to 29.6 ppb
2007-03-2923.5 ppb1710 to 40.1 ppb
2007-03-2825.15 ppb15011 to 32.8 ppb
2007-02-159.71 ppb1360 to 33.4 ppb
2007-01-2514.45 ppb1710 to 23.5 ppb
2007-01-2314.55 ppb1505.2 to 20.6 ppb
2006-12-200.58 ppb430 to 2.3 ppb
2006-12-070.25 ppb210 to 0.5 ppb
2006-10-2613.03 ppb1350 to 56.9 ppb
2006-08-1020.48 ppb1780 to 53.2 ppb
2006-07-206.61 ppb1480 to 26.3 ppb
2006-05-1015.06 ppb1020 to 30.3 ppb
2006-04-136.52 ppb1370 to 19.7 ppb
2006-02-220.75 ppb1290 to 6.1 ppb
2006-02-210.35 ppb210 to 0.7 ppb
2006-02-086.15 ppb1370 to 20.3 ppb
2005-12-190 ppb660 ppb
2005-11-033.77 ppb1380 to 12 ppb
2005-10-270.65 ppb650 to 3.9 ppb
2005-07-270.04 ppb28260 to 0.6 ppb
2005-07-2611.86 ppb1860 to 21.5 ppb
2005-07-2111.14 ppb1790 to 83 ppb
2005-07-204.58 ppb1270 to 18 ppb
2005-05-057.55 ppb1080 to 72 ppb
2005-05-045.88 ppb18140 to 100 ppb
2005-04-1411.02 ppb1370 to 39.1 ppb
2005-04-130 ppb440 ppb
2005-01-276.61 ppb1180 to 26.1 ppb
2005-01-261.99 ppb24200 to 22 ppb
2004-11-046.55 ppb1280 to 25.8 ppb
2004-11-0316.78 ppb1010 to 24.4 ppb
2004-08-1226.54 ppb1630 to 48.2 ppb
2004-07-0818.86 ppb1690 to 56.1 ppb
2004-04-2936 ppb2035.7 to 36.3 ppb
2004-04-2118.04 ppb2070 to 40.3 ppb
2004-02-268.71 ppb1570 to 26.5 ppb
2004-01-2817.83 ppb3012.3 to 23.7 ppb
2004-01-2711.8 ppb620 to 25 ppb
2004-01-260.3 ppb320 to 0.9 ppb
2004-01-200 ppb110 ppb
2004-01-145.9 ppb310 to 17 ppb
2004-01-135.9 ppb740 to 20.8 ppb