1,4-Dioxane
Golden State Water Company - Cowan Heights
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 |
|---|---|---|---|---|
| 2014 | 0.0147 ppb | 6 | 1 | ND - 0.0880 ppb |
| 2015 | ND | 2 | 0 | ND |
| 2016 | ND | 2 | 0 | ND |
| 2017 | ND | 2 | 0 | ND |
| 2018 | ND | 2 | 0 | ND |
| 2019 | ND | 2 | 0 | ND |
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 |
|---|---|---|
| 2014-02-19 | 4417-001-0940 | ND |
| 2014-02-19 | 4417-004-0925 | ND |
| 2014-05-20 | 106914Q | ND |
| 2014-08-19 | 108811P | ND |
| 2014-08-19 | 108810P | 0.0880 ppb |
| 2014-11-19 | 109646P | ND |
| 2015-02-02 | 4417-001-0830 | ND |
| 2015-02-02 | 4417-004-0850 | ND |
| 2016-01-19 | 4417-001-0835 | ND |
| 2016-01-19 | 4417-004-0850 | ND |
| 2017-01-10 | 4417-001-0925 | ND |
| 2017-01-10 | 4417-004-0940 | ND |
| 2018-01-08 | 4417-001-0930 | ND |
| 2018-01-08 | 4417-004-0905 | ND |
| 2019-03-25 | 4417-001-0855 | ND |
| 2019-03-25 | 4417-004-0840 | ND |