EWG's Tap Water Database — 2019 UPDATE



Chesterfield Rural Water

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.

Click here to read more about 1,4-dioxane.





Samples exceeding legal limit (MCL)


Samples exceeding
health guidelines

Testing results - average by year

YearAverage resultSamples takenDetectionsRange of results
20130.280 ppb330.120 ppb - 0.590 ppb
20140.330 ppb330.160 ppb - 0.490 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
2013-08-19201308210444AM0.590 ppb
2013-08-19201308210383AM0.130 ppb
2013-11-20201311220548AM0.120 ppb
2014-02-19201402210299AM0.160 ppb
2014-02-19201402210357AM0.490 ppb
2014-05-21201405230217AM0.340 ppb