1,4-Dioxane
Golden State Water Company (GSWC) - Norwalk
1,4-Dioxane is a solvent classified by the EPA as a likely human carcinogen. It contaminates groundwater in many states due to industrial wastewater discharges, plastic manufacturing runoff and landfill runoff. Read More.
Animal studies show that 1,4-dioxane can target the liver, kidneys and respiratory system, and that prenatal exposure can harm the developing fetus. The State of California has set a Public Heatlh Goal of no more than 1 part per billion of 1,4-dioxane in drinking water. The state of Massachusetts sets a legal limit of 0.3 ppb, and New Hampshire's limit is 3 parts per billion. There is no national drinking water standard for this contaminant.
Samples
Samples exceeding legal limit (MCL)
Samples exceeding
health guidelines
Testing results - average by year
| Year | Average result | Samples taken | Detections | Range of results |
|---|---|---|---|---|
| 2013 | 2.48 ppb | 4 | 3 | ND - 5.30 ppb |
| 2014 | 1.54 ppb | 15 | 9 | ND - 5.90 ppb |
| 2015 | 1.76 ppb | 5 | 4 | ND - 3.20 ppb |
| 2016 | 2.24 ppb | 5 | 5 | 1.10 ppb - 3.30 ppb |
| 2017 | 3.55 ppb | 4 | 4 | 1.60 ppb - 5.00 ppb |
| 2018 | 3.25 ppb | 4 | 4 | 2.90 ppb - 3.60 ppb |
| 2019 | 2.70 ppb | 2 | 2 | 2.60 ppb - 2.80 ppb |
ppb = parts per billion
State and national drinking water standards and health guidelines
EWG Health Guideline 0.35 ppb
The EWG Health Guideline of 0.35 ppb for 1,4-dioxane was defined by the Environmental Protection Agency 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 |
|---|---|---|
| 2013-10-18 | 201310180541AM | 1.30 ppb |
| 2013-10-18 | 201310180545AM | 3.30 ppb |
| 2013-10-18 | 201310180547AM | ND |
| 2013-10-18 | 201310180543AM | 5.30 ppb |
| 2014-01-17 | 201401180029AM | 0.860 ppb |
| 2014-01-17 | 201401180031AM | ND |
| 2014-03-12 | 2706-010-0938 | ND |
| 2014-04-17 | 201404180109AM | 1.60 ppb |
| 2014-04-17 | 201404180115AM | ND |
| 2014-04-17 | 201404180113AM | 3.90 ppb |
| 2014-04-17 | 201404180111AM | 5.90 ppb |
| 2014-05-07 | 2706-010-1035 | ND |
| 2014-05-28 | 2706-016-1028 | 1.50 ppb |
| 2014-06-04 | 201406050293AM | 3.50 ppb |
| 2014-07-17 | 201407170807AM | ND |
| 2014-08-04 | 2706-010-1150 | ND |
| 2014-08-13 | 2706-016-0939 | 1.70 ppb |
| 2014-11-04 | 2706-016-1054 | 2.90 ppb |
| 2014-11-04 | 2706-010-0930 | 1.30 ppb |
| 2015-02-02 | 2706-010-1014 | 1.70 ppb |
| 2015-02-03 | 2706-016-1152 | 3.20 ppb |
| 2015-05-07 | 2706-016-1358 | ND |
| 2015-08-04 | 2706-016-0821 | 2.20 ppb |
| 2015-11-04 | 2706-016-1304 | 1.70 ppb |
| 2016-02-03 | 2706-010-1535 | 1.10 ppb |
| 2016-02-04 | 2706-016-0905 | 2.30 ppb |
| 2016-05-04 | 2706-016-0921 | 2.60 ppb |
| 2016-08-02 | 2706-016-1146 | 1.90 ppb |
| 2016-11-08 | 2706-016-1303 | 3.30 ppb |
| 2017-02-14 | 9590-010-1020 | 1.60 ppb |
| 2017-05-09 | 9590-016-0940 | 4.20 ppb |
| 2017-08-01 | 9590-016-1029 | 3.40 ppb |
| 2017-11-09 | 9590-016-1103 | 5.00 ppb |
| 2018-02-08 | 9590-016-1401 | 3.30 ppb |
| 2018-05-02 | 9590-016-1147 | 3.60 ppb |
| 2018-08-06 | 9590-016-1106 | 2.90 ppb |
| 2018-11-06 | 9590-016-1203 | 3.20 ppb |
| 2019-02-11 | 9590-016-1054 | 2.80 ppb |
| 2019-05-08 | 9590-016-1140 | 2.60 ppb |