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EWG's Tap Water Database — 2021 UPDATE

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Chloroform

Dover Water Department

Chloroform, one of the total trihalomethanes (TTHMs), is formed when chlorine or other disinfectants are used to treat drinking water. Chloroform and other disinfection byproducts increase the risk of cancer and may cause problems during pregnancy. Read More.

In addition to tap water disinfection, chloroform pollution in the environment also comes from industrial discharges from pulp and paper mills, and from urban wastewater effluent. Human studies show that chloroform damages the kidneys, liver and central nervous system. In animals, chloroform causes infertility, birth defects and cancer.

Click here to read more about disinfection byproducts.

MORE ABOUT THIS CONTAMINANT

 

175

Samples

0

Samples exceeding legal limit (MCL)

149

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20149.30 ppb3428ND - 37.7 ppb
201510.2 ppb3328ND - 41.8 ppb
201616.6 ppb2017ND - 35.0 ppb
201712.7 ppb3127ND - 44.0 ppb
201819.6 ppb2120ND - 40.0 ppb
20198.80 ppb3629ND - 30.5 ppb

ppb = parts per billion

State and national drinking water standards and health guidelines

EWG Health Guideline 0.4 ppb

The EWG Health Guideline of 0.4 ppb for chloroform was proposed in 2018 by the California Office of Environmental Health Hazard Assessment as a one-in-a-million lifetime risk of cancer. Values greater than one-in-a-million cancer risk level can result in increased cancer cases above one in a million people.

ppb = parts per billion

All test results

Date Lab ID Result
2014-01-31S238393ND
2014-03-18L4982245-1 TTHM20.6 ppb
2014-03-18L4982245-2 TTHM8.94 ppb
2014-03-18L4982245-3 TTHM9.76 ppb
2014-03-18L4982245-4 TTHM12.9 ppb
2014-04-16S268406ND
2014-05-19S4950071.73 ppb
2014-06-12L5106837-1-TTHM23.8 ppb
2014-06-12L5106837-2-TTHM12.7 ppb
2014-06-12L5106837-3-TTHM10.4 ppb
2014-06-12L5106837-4-TTHM24.0 ppb
2014-08-15S2620911.80 ppb
2014-08-15S2620920.560 ppb
2014-08-15S262093ND
2014-08-15S2620941.93 ppb
2014-08-15S2620954.14 ppb
2014-08-15S2620960.500 ppb
2014-08-15S262097ND
2014-09-08L5241778-1 TTHM14.2 ppb
2014-09-08L5241778-2 TTHM13.1 ppb
2014-09-08L5241778-3 TTHM16.8 ppb
2014-09-08L5241778-4 TTHM25.7 ppb
2014-09-15S2620901.09 ppb
2014-09-15S2620984.24 ppb
2014-09-15S2620995.73 ppb
2014-09-15S2621001.11 ppb
2014-09-15S262102ND
2014-09-15S262103ND
2014-09-29L5279641-183.41 ppb
2014-11-17S2513850.510 ppb
2014-12-03L5352430-1 TTHM28.9 ppb
2014-12-03L5352430-2 TTHM12.2 ppb
2014-12-03L5352430-3 TTHM17.6 ppb
2014-12-03L5352430-4 TTHM37.7 ppb
2015-01-15S2621150.560 ppb
2015-03-02L5484011-1-TTHM17.8 ppb
2015-03-02L5484011-2-TTHM11.0 ppb
2015-03-02L5484011-3-TTHM13.2 ppb
2015-03-02L5484011-4-TTHM28.5 ppb
2015-05-22S5749100.680 ppb
2015-05-26L5609090-122.0 ppb
2015-05-26L5609090-2-TTHM10.4 ppb
2015-05-26L5609090-3-TTHM11.6 ppb
2015-05-26L5609090-4-TTHM41.8 ppb
2015-08-27L5783279-1 TTHM12.8 ppb
2015-08-27L5783279-2 TTHM14.7 ppb
2015-08-27L5783279-3 TTHM6.20 ppb
2015-08-27L5783279-4 TTHM21.5 ppb
2015-11-18L5919691-1 TTHM26.3 ppb
2015-11-18L5919691-2 TTHM22.0 ppb
2015-11-18L5919691-3 TTHM21.9 ppb
2015-11-18L5919691-4 TTHM29.6 ppb
2015-12-07S2383684.71 ppb
2015-12-07S2383694.46 ppb
2015-12-11S4974110.910 ppb
2015-12-11S497412ND
2015-12-11S4974130.550 ppb
2015-12-11S4974142.05 ppb
2015-12-14S4974271.94 ppb
2015-12-14S497430ND
2015-12-14S4974313.65 ppb
2015-12-14S4974321.89 ppb
2015-12-14S4974333.60 ppb
2015-12-14S497435ND
2015-12-17S4974281.35 ppb
2015-12-20S268410ND
2015-12-27S251387ND
2016-02-11L6073199-1 TTHM23.0 ppb
2016-02-11L6073199-2 TTHM12.0 ppb
2016-02-11L6073199-3 TTHM14.0 ppb
2016-02-11L6073199-4 TTHM20.0 ppb
2016-02-18S497452ND
2016-05-10L6246380-1 TTHM24.0 ppb
2016-05-10L6246380-2 TTHM12.0 ppb
2016-05-10L6246380-3 TTHM24.0 ppb
2016-05-10L6246380-4 TTHM26.0 ppb
2016-06-14S677171ND
2016-08-08L6415584-124.0 ppb
2016-08-08L6415584-213.0 ppb
2016-08-08L6415584-318.0 ppb
2016-08-08L6415584-435.0 ppb
2016-10-04S6372190.540 ppb
2016-11-02L6541220-1 TTHM24.0 ppb
2016-11-02L6541220-2 TTHM17.0 ppb
2016-11-02L6541220-3 TTHM14.0 ppb
2016-11-02L6541220-4 TTHM31.0 ppb
2016-12-21S637222ND
2017-01-26L6650711-1 TTHM24.0 ppb
2017-01-26L6650711-2 TTHM1.50 ppb
2017-01-26L6650711-3 TTHM8.50 ppb
2017-01-26L6650711-4 TTHM21.0 ppb
2017-04-24L6772990-1 TTHM24.0 ppb
2017-04-24L6772990-2 TTHM18.0 ppb
2017-04-24L6772990-3 TTHM28.0 ppb
2017-04-24L6772990-4 TTHM29.0 ppb
2017-07-24L6921063-1 TTHM23.0 ppb
2017-07-24L6921063-2 TTHM16.0 ppb
2017-07-24L6921063-3 TTHM13.0 ppb
2017-07-24L6921063-4 TTHM31.0 ppb
2017-10-25L6965247-1 TTHM33.0 ppb
2017-10-25L6965247-2 TTHM44.0 ppb
2017-10-25L6965247-3 TTHM17.0 ppb
2017-10-25L6965247-4 TTHM24.0 ppb
2017-12-12S63721615.2 ppb
2017-12-20S7710910.740 ppb
2017-12-20S7710933.69 ppb
2017-12-20S771095ND
2017-12-20S771097ND
2017-12-20S7710993.67 ppb
2017-12-20S7711014.09 ppb
2017-12-20S7711030.580 ppb
2017-12-20S771105ND
2017-12-20S7711072.26 ppb
2017-12-20S7711093.46 ppb
2017-12-20S7711113.33 ppb
2017-12-20S7711131.52 ppb
2017-12-20S7711150.690 ppb
2017-12-20S771117ND
2018-01-11L6992217-1 TTHM21.0 ppb
2018-01-11L6992217-2 TTHM18.0 ppb
2018-01-11L6992217-3 TTHM28.0 ppb
2018-01-11L6992217-4 TTHM16.0 ppb
2018-04-02L7013585-1 TTHM20.0 ppb
2018-04-02L7013585-2 TTHM18.0 ppb
2018-04-02L7013858-3 TTHM27.0 ppb
2018-04-02L7013858-4 TTHM26.0 ppb
2018-09-17L7073682-1 TTHM26.0 ppb
2018-09-17L7073682-3 TTHM40.0 ppb
2018-09-17L7073682-5 TTHM33.0 ppb
2018-09-18L7073683-1 TTHM21.0 ppb
2018-09-27S7820170.550 ppb
2018-09-27S7820212.97 ppb
2018-09-27S7820230.600 ppb
2018-09-27S782025ND
2018-12-11L7089492-1 TTHM23.0 ppb
2018-12-11L7089492-2 TTHM21.0 ppb
2018-12-11L7089492-3 TTHM32.0 ppb
2018-12-11L7089492-4 TTHM34.0 ppb
2018-12-13S5041583.77 ppb
2019-03-07L7108274-1 TTHM19.0 ppb
2019-03-07L7108274-3 TTHM15.0 ppb
2019-03-07L7108274-5 TTHM16.0 ppb
2019-03-07L7108274-7 TTHM18.0 ppb
2019-04-12S872258ND
2019-04-16S5041763.13 ppb
2019-06-05S77112122.8 ppb
2019-06-05S7711263.57 ppb
2019-06-05S88926018.5 ppb
2019-06-05S88926427.5 ppb
2019-06-05S88926810.2 ppb
2019-08-20S8485500.860 ppb
2019-08-20S8485511.95 ppb
2019-08-20S848552ND
2019-08-20S848553ND
2019-08-20S8485542.68 ppb
2019-08-20S8485560.520 ppb
2019-08-20S848557ND
2019-08-20S8485581.83 ppb
2019-08-20S8485592.95 ppb
2019-08-20S8485603.03 ppb
2019-08-20S8485611.19 ppb
2019-08-20S8485620.590 ppb
2019-08-20S848563ND
2019-08-20S848564ND
2019-08-20S848576ND
2019-09-03S8482403.97 ppb
2019-09-03S84824416.5 ppb
2019-09-03S84824818.4 ppb
2019-09-03S84825223.9 ppb
2019-11-20S8482544.00 ppb
2019-11-20S9251803.26 ppb
2019-11-21S84826814.6 ppb
2019-11-21S84827030.5 ppb
2019-11-21S84827216.3 ppb
2019-11-21S84827416.3 ppb