EWG's Tap Water Database — 2021 UPDATE



Greenlawn WD

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
20130.328 ppb1917ND - 1.30 ppb
20141.60 ppb111.60 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
2013-06-25781750.120 ppb
2013-06-25781810.110 ppb
2013-06-25782600.870 ppb
2013-06-25781670.140 ppb
2013-06-26781780.320 ppb
2013-06-26782631.30 ppb
2013-06-26781830.330 ppb
2013-06-26782660.370 ppb
2013-06-26781700.250 ppb
2013-12-1278170 (DECEMBER)0.270 ppb
2013-12-1278175 (DECEMBER)0.0900 ppb
2013-12-1278181 (DECEMBER)0.210 ppb
2013-12-1278178 (DECEMBER)0.300 ppb
2013-12-1278167 (DECEMBER)0.1000 ppb
2013-12-1678266 (EP009)0.320 ppb
2013-12-1678268 (EP010)ND
2013-12-1678183 (EP006)0.350 ppb
2013-12-1678260 (EP007)0.780 ppb
2014-11-1778263 1120141.60 ppb