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EWG's Tap Water Database — 2019 UPDATE

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Total trihalomethanes (TTHMs)

City of Sugar Land

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.

In 2010, the California Office of Environmental Health Hazard Assessment published a draft public health goal for the trihalomethanes group at 0.8 parts per billion, or 100 times lower than the federal legal limit of 80 parts per billion for this contaminant group.

Click here to read more about disinfection byproducts.

 

160

Samples

0

Samples exceeding legal limit (MCL)

118

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20120.933 ppb93ND - 5.00 ppb
20131.10 ppb248ND - 6.60 ppb
20145.51 ppb3130ND - 11.3 ppb
20152.38 ppb3227ND - 6.60 ppb
20162.27 ppb3228ND - 6.60 ppb
20172.17 ppb3222ND - 5.70 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
2012-05-11AB89673ND
2012-05-11AB89674ND
2012-05-11AB89668ND
2012-05-11AB896705.00 ppb
2012-05-11AB89669ND
2012-10-02AC024261.10 ppb
2012-10-02AC024282.30 ppb
2012-10-02AC02424ND
2012-10-02AC02425ND
2013-01-24AC08664ND
2013-01-24AC086514.60 ppb
2013-01-24AC086541.40 ppb
2013-01-24AC086551.10 ppb
2013-04-24AC17664ND
2013-04-24AC176656.60 ppb
2013-04-24AC17663ND
2013-04-24AC17666ND
2013-07-15AC245853.00 ppb
2013-07-15AC245895.00 ppb
2013-07-15AC24591ND
2013-07-15AC24590ND
2013-07-15AC245942.90 ppb
2013-07-15AC24593ND
2013-07-15AC24592ND
2013-07-15AC24595ND
2013-11-08AC34713ND
2013-11-08AC34709ND
2013-11-08AC34711ND
2013-11-08AC34710ND
2013-11-08AC34715ND
2013-11-08AC347121.70 ppb
2013-11-08AC34708ND
2013-11-08AC34714ND
2014-02-11AC421952.70 ppb
2014-02-11AC422004.20 ppb
2014-02-11AC421924.40 ppb
2014-02-11AC421994.30 ppb
2014-02-11AC422012.60 ppb
2014-02-11AC421937.00 ppb
2014-02-11AC421984.80 ppb
2014-04-29AC522118.60 ppb
2014-04-29AC521929.50 ppb
2014-04-29AC521953.80 ppb
2014-04-29AC521937.40 ppb
2014-04-29AC522122.50 ppb
2014-04-29AC521968.80 ppb
2014-04-29AC521712.70 ppb
2014-04-29AC521948.00 ppb
2014-07-23AC607705.60 ppb
2014-07-23AC6073911.3 ppb
2014-07-23AC607956.30 ppb
2014-07-23AC607408.10 ppb
2014-07-23AC607692.50 ppb
2014-07-23AC607834.20 ppb
2014-07-23AC60764ND
2014-07-23AC607656.60 ppb
2014-10-14AC696575.50 ppb
2014-10-14AC696565.00 ppb
2014-10-14AC696555.50 ppb
2014-10-14AC696545.70 ppb
2014-10-14AC696697.00 ppb
2014-10-14AC696486.20 ppb
2014-10-14AC696504.70 ppb
2014-10-14AC696515.20 ppb
2015-01-22AC774182.30 ppb
2015-01-22AC774103.50 ppb
2015-01-22AC774193.30 ppb
2015-01-22AC774263.60 ppb
2015-01-22AC774153.50 ppb
2015-01-22AC774273.90 ppb
2015-01-22AC774136.50 ppb
2015-01-22AC774092.20 ppb
2015-06-02AC942751.30 ppb
2015-06-02AC942681.60 ppb
2015-06-02AC942761.20 ppb
2015-06-02AC942691.40 ppb
2015-06-02AC94288ND
2015-06-02AC942781.60 ppb
2015-06-02AC94261ND
2015-06-02AC942871.20 ppb
2015-07-16AC999363.40 ppb
2015-07-16AC99920ND
2015-07-16AC999324.40 ppb
2015-07-16AC999301.30 ppb
2015-07-16AC999111.30 ppb
2015-07-16AC999196.60 ppb
2015-07-16AC99929ND
2015-07-16AC999274.80 ppb
2015-11-04AD126022.00 ppb
2015-11-04AD126154.60 ppb
2015-11-04AD126122.00 ppb
2015-11-04AD125692.20 ppb
2015-11-04AD126131.40 ppb
2015-11-04AD125683.30 ppb
2015-11-04AD12609ND
2015-11-04AD126141.90 ppb
2016-02-02AD214361.50 ppb
2016-02-02AD214312.60 ppb
2016-02-02AD214381.70 ppb
2016-02-02AD214391.40 ppb
2016-02-02AD214331.40 ppb
2016-02-02AD214372.20 ppb
2016-02-02AD214411.10 ppb
2016-02-02AD214421.60 ppb
2016-04-19AD335741.50 ppb
2016-04-19AD335772.30 ppb
2016-04-19AD335641.40 ppb
2016-04-19AD335721.70 ppb
2016-04-19AD335731.20 ppb
2016-04-19AD335752.50 ppb
2016-04-19AD335681.30 ppb
2016-04-19AD335781.30 ppb
2016-09-01AD476465.20 ppb
2016-09-01AD476794.40 ppb
2016-09-01AD476436.60 ppb
2016-09-01AD476502.40 ppb
2016-09-01AD476471.60 ppb
2016-09-01AD476814.90 ppb
2016-09-01AD476481.10 ppb
2016-09-01AD476445.90 ppb
2016-10-05AD525342.60 ppb
2016-10-05AD52537ND
2016-10-05AD525391.90 ppb
2016-10-05AD525285.00 ppb
2016-10-05AD52536ND
2016-10-05AD52538ND
2016-10-05AD52530ND
2016-10-05AD525324.30 ppb
2017-01-04AD629584.80 ppb
2017-01-04AD629683.10 ppb
2017-01-04AD629533.30 ppb
2017-01-04AD629665.70 ppb
2017-01-04AD629612.70 ppb
2017-01-04AD62960ND
2017-01-04AD62954ND
2017-01-04AD629553.30 ppb
2017-04-03AD780294.30 ppb
2017-04-03AD780333.70 ppb
2017-04-03AD780271.40 ppb
2017-04-03AD780321.40 ppb
2017-04-03AD780261.30 ppb
2017-04-03AD780311.30 ppb
2017-04-03AD78030ND
2017-04-03AD780281.30 ppb
2017-07-05AD883052.90 ppb
2017-07-05AD88306ND
2017-07-05AD883024.50 ppb
2017-07-05AD882995.60 ppb
2017-07-05AD88303ND
2017-07-05AD883013.20 ppb
2017-07-05AD88304ND
2017-07-05AD883004.20 ppb
2017-10-02AD987633.10 ppb
2017-10-02AD98776ND
2017-10-02AD98780ND
2017-10-02AD987703.50 ppb
2017-10-02AD98774ND
2017-10-02AD987772.80 ppb
2017-10-02AD98781ND
2017-10-02AD987792.00 ppb