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EWG's Tap Water Database — 2021 UPDATE

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Total trihalomethanes (TTHMs)

Baton Rouge Water Company

Trihalomethanes are cancer-causing contaminants that form during water treatment with chlorine and other disinfectants. The total trihalomethanes group includes four chemicals: chloroform, bromodichloromethane, dibromochloromethane and bromoform. Read More.

Studies conducted in the U.S. and Europe have found that drinking tap water that carries disinfection byproducts increases the risk of developing bladder cancer. In animal studies, all trihalomethanes cause liver, kidney and intestinal tumors. Some human epidemiological studies also reported an association between disinfection byproducts and an increased risk of problems during pregnancy, including spontaneous miscarriage, cardiovascular defects, neural tube defects and low birth weight.

The health guideline of 0.15 parts per billion, or ppb, for the group of four trihalomethanes, or THM4/TTHM, was defined in a peer-reviewed scientific study by EWG and represents a one-in-one-million lifetime cancer risk level.

Click here to read more about disinfection byproducts.

MORE ABOUT THIS CONTAMINANT

 

220

Samples

0

Samples exceeding legal limit (MCL)

120

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20142.78 ppb4826ND - 19.3 ppb
20151.80 ppb4416ND - 9.70 ppb
20162.13 ppb3212ND - 7.80 ppb
20171.87 ppb3228ND - 6.00 ppb
20181.42 ppb3220ND - 5.50 ppb
20191.64 ppb3218ND - 6.90 ppb

ppb = parts per billion

State and national drinking water standards and health guidelines

EWG Health Guideline 0.15 ppb

The health guideline of 0.15 parts per billion, or ppb, for the group of four trihalomethanes, or THM4/TTHM, was defined in a peer-reviewed scientific study by EWG and represents a one-in-one-million lifetime cancer risk level.

EPA Maximum Contaminant
Level (MCL) 80 ppb

The legal limit for the group of four trihalomethanes, established in 1998, was based on the need for residual disinfectant levels in water served to customers and the cost of treatment. This limit does not fully protect against the risk of cancer due to exposure to trihalomethanes.

ppb = parts per billion

All test results

Date Lab ID Result
2014-01-14201158146ND
2014-01-14201158146ND
2014-01-152011581491.40 ppb
2014-01-152011581501.10 ppb
2014-01-152011581510.860 ppb
2014-01-1520115815219.3 ppb
2014-01-15201158153ND
2014-01-152011581491.40 ppb
2014-01-152011581501.10 ppb
2014-01-152011581510.860 ppb
2014-01-1520115815219.3 ppb
2014-01-15201158153ND
2014-04-15202865004ND
2014-04-15202865005ND
2014-04-1520286500618.3 ppb
2014-04-15202866002ND
2014-04-15202866003ND
2014-04-152028660067.00 ppb
2014-04-15202865004ND
2014-04-15202865005ND
2014-04-1520286500618.3 ppb
2014-04-15202866002ND
2014-04-15202866003ND
2014-04-152028660067.00 ppb
2014-07-17207090001ND
2014-07-17207090002ND
2014-07-17207090003ND
2014-07-172070900045.80 ppb
2014-07-17207090005ND
2014-07-17207090006ND
2014-07-17207090001ND
2014-07-17207090002ND
2014-07-17207090003ND
2014-07-172070900045.80 ppb
2014-07-17207090005ND
2014-07-17207090006ND
2014-10-1720112230011.40 ppb
2014-10-1720112230021.20 ppb
2014-10-1720112230031.20 ppb
2014-10-1720112230041.20 ppb
2014-10-1720112230056.80 ppb
2014-10-1720112230061.10 ppb
2014-10-1720112230011.40 ppb
2014-10-1720112230021.20 ppb
2014-10-1720112230031.20 ppb
2014-10-1720112230041.20 ppb
2014-10-1720112230056.80 ppb
2014-10-1720112230061.10 ppb
2015-01-142015090001ND
2015-01-142015090002ND
2015-01-1420150900039.70 ppb
2015-01-142015090004ND
2015-01-142015090005ND
2015-01-1420150900061.20 ppb
2015-01-142015090001ND
2015-01-142015090002ND
2015-01-1420150900039.70 ppb
2015-01-142015090004ND
2015-01-142015090005ND
2015-01-1420150900061.20 ppb
2015-04-1720188260017.90 ppb
2015-04-172018826002ND
2015-04-172018826003ND
2015-04-1720188260044.70 ppb
2015-04-172018826005ND
2015-04-172018826006ND
2015-04-1720188260017.90 ppb
2015-04-172018826002ND
2015-04-172018826003ND
2015-04-1720188260044.70 ppb
2015-04-172018826005ND
2015-04-172018826006ND
2015-07-1520228190012.80 ppb
2015-07-152022819002ND
2015-07-152022819003ND
2015-07-1520228190045.40 ppb
2015-07-152022819005ND
2015-07-152022819006ND
2015-07-1520228190012.80 ppb
2015-07-152022819002ND
2015-07-152022819003ND
2015-07-1520228190045.40 ppb
2015-07-152022819005ND
2015-07-152022819006ND
2015-10-152027291001ND
2015-10-152027291002ND
2015-10-1520272910031.000 ppb
2015-10-1520272910046.90 ppb
2015-10-152027291001ND
2015-10-152027291002ND
2015-10-1520272910031.000 ppb
2015-10-1520272910046.90 ppb
2016-01-152031365001ND
2016-01-1520313650026.30 ppb
2016-01-1520313650037.60 ppb
2016-01-1520313650041.000 ppb
2016-01-152031365001ND
2016-01-1520313650026.30 ppb
2016-01-1520313650037.60 ppb
2016-01-1520313650041.000 ppb
2016-04-182035422001ND
2016-04-1820354220026.10 ppb
2016-04-182035422003ND
2016-04-182035422004ND
2016-04-182035422001ND
2016-04-1820354220026.10 ppb
2016-04-182035422003ND
2016-04-182035422004ND
2016-07-182040020001ND
2016-07-1820400200025.20 ppb
2016-07-18204002003ND
2016-07-18204020004ND
2016-07-182040020001ND
2016-07-1820400200025.20 ppb
2016-07-18204002003ND
2016-07-18204020004ND
2016-10-202044503001ND
2016-10-2020445030027.80 ppb
2016-10-202044503003ND
2016-10-202044503004ND
2016-10-202044503001ND
2016-10-2020445030027.80 ppb
2016-10-202044503003ND
2016-10-202044503004ND
2017-01-20352901910020.580 ppb
2017-01-20352901910030.990 ppb
2017-01-20352901910040.560 ppb
2017-01-20352901910055.70 ppb
2017-01-20352901910020.580 ppb
2017-01-20352901910030.990 ppb
2017-01-20352901910040.560 ppb
2017-01-20352901910055.70 ppb
2017-04-13353065080030.710 ppb
2017-04-13353065080040.550 ppb
2017-04-13353065080050.520 ppb
2017-04-13353065080065.80 ppb
2017-04-13353065080030.710 ppb
2017-04-13353065080040.550 ppb
2017-04-13353065080050.520 ppb
2017-04-13353065080065.80 ppb
2017-07-07353226210070.760 ppb
2017-07-0735322621008ND
2017-07-0735322621009ND
2017-07-07353226210106.00 ppb
2017-07-07353226210070.760 ppb
2017-07-0735322621008ND
2017-07-0735322621009ND
2017-07-07353226210106.00 ppb
2017-10-05353406360012.10 ppb
2017-10-05353406360020.490 ppb
2017-10-05353406360030.570 ppb
2017-10-05353406360044.60 ppb
2017-10-05353406360012.10 ppb
2017-10-05353406360020.490 ppb
2017-10-05353406360030.570 ppb
2017-10-05353406360044.60 ppb
2018-01-12353683490011.10 ppb
2018-01-12353683490020.600 ppb
2018-01-12353683490030.460 ppb
2018-01-12353683490045.30 ppb
2018-01-12353683490011.10 ppb
2018-01-12353683490020.600 ppb
2018-01-12353683490030.460 ppb
2018-01-12353683490045.30 ppb
2018-04-13353861440011.50 ppb
2018-04-1335386144002ND
2018-04-1335386144003ND
2018-04-1335386144004ND
2018-04-13353861440011.50 ppb
2018-04-1335386144002ND
2018-04-1335386144003ND
2018-04-1335386144004ND
2018-07-06354026090010.900 ppb
2018-07-0635402609002ND
2018-07-06354026090030.560 ppb
2018-07-06354026090045.50 ppb
2018-07-06354026090010.900 ppb
2018-07-0635402609002ND
2018-07-06354026090030.560 ppb
2018-07-06354026090045.50 ppb
2018-10-12354240300011.50 ppb
2018-10-1235424030002ND
2018-10-1235424030003ND
2018-10-12354240300045.30 ppb
2018-10-12354240300011.50 ppb
2018-10-1235424030002ND
2018-10-1235424030003ND
2018-10-12354240300045.30 ppb
2019-01-17354431630011.20 ppb
2019-01-1735443163002ND
2019-01-1735443163003ND
2019-01-17354431630046.90 ppb
2019-01-17354431630011.20 ppb
2019-01-1735443163002ND
2019-01-1735443163003ND
2019-01-17354431630046.90 ppb
2019-04-0835460486001ND
2019-04-0835460486002ND
2019-04-0835460486003ND
2019-04-08354604860045.10 ppb
2019-04-0835460486001ND
2019-04-0835460486002ND
2019-04-0835460486003ND
2019-04-08354604860045.10 ppb
2019-07-18354835350010.520 ppb
2019-07-18354835350020.420 ppb
2019-07-18354835350030.510 ppb
2019-07-18354835350045.50 ppb
2019-07-18354835350010.520 ppb
2019-07-18354835350020.420 ppb
2019-07-18354835350030.510 ppb
2019-07-18354835350045.50 ppb
2019-10-18355062380010.740 ppb
2019-10-1835506238002ND
2019-10-1835506238003ND
2019-10-18355062380045.30 ppb
2019-10-18355062380010.740 ppb
2019-10-1835506238002ND
2019-10-1835506238003ND
2019-10-18355062380045.30 ppb