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EWG's Tap Water Database — 2019 UPDATE

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Arsenic

Washington Aqueduct Division

Arsenic is a potent carcinogen and common contaminant in drinking water. Arsenic causes thousands of cases of cancer each year in the U.S. Click here to read more about arsenic.

 

143

Samples

0

Samples exceeding legal limit (MCL)

53

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20120.0208 ppb241ND - 0.500 ppb
20130.183 ppb248ND - 0.600 ppb
20140.158 ppb2411ND - 0.500 ppb
20150.163 ppb2412ND - 0.400 ppb
20160.138 ppb2412ND - 0.400 ppb
20170.109 ppb239ND - 0.400 ppb

ppb = parts per billion

State and national drinking water standards and health guidelines

EWG Health Guideline 0.004 ppb

The EWG Health Guideline of 0.004 ppb for arsenic was defined by the California Office of Environmental Health Hazard Assessment as a public health goal, the level of a drinking water contaminant that does not pose a significant health risk. This health guideline protects against cancer.

EPA Maximum Contaminant
Level (MCL) 10 ppb

The legal limit for arsenic, established in 2001, was based on costs for arsenic removal, as calculated at the time that the standard was set. This limit does not fully protect against the risk of cancer due to arsenic exposure.

ppb = parts per billion

All test results

Date Lab ID Result
2012-01-01DalecarliaND
2012-01-01McMillanND
2012-02-01DalecarliaND
2012-02-01McMillanND
2012-03-01DalecarliaND
2012-03-01McMillanND
2012-04-01DalecarliaND
2012-04-01McMillanND
2012-05-01DalecarliaND
2012-05-01McMillanND
2012-06-01DalecarliaND
2012-06-01McMillanND
2012-07-01DalecarliaND
2012-07-01McMillanND
2012-08-01Dalecarlia0.500 ppb
2012-08-01McMillanND
2012-09-01DalecarliaND
2012-09-01McMillanND
2012-10-01DalecarliaND
2012-10-01McMillanND
2012-11-01DalecarliaND
2012-11-01McMillanND
2012-12-01DalecarliaND
2012-12-01McMillanND
2013-01-01DalecarliaND
2013-01-01McMillanND
2013-02-01DalecarliaND
2013-02-01McMillanND
2013-03-01DalecarliaND
2013-03-01McMillanND
2013-04-01DalecarliaND
2013-04-01McMillanND
2013-05-01DalecarliaND
2013-05-01McMillanND
2013-06-01DalecarliaND
2013-06-01McMillanND
2013-07-01Dalecarlia0.600 ppb
2013-07-01McMillan0.500 ppb
2013-08-01Dalecarlia0.600 ppb
2013-08-01McMillan0.500 ppb
2013-09-01Dalecarlia0.600 ppb
2013-09-01McMillan0.500 ppb
2013-10-01Dalecarlia0.600 ppb
2013-10-01McMillan0.500 ppb
2013-11-01DalecarliaND
2013-11-01McMillanND
2013-12-01DalecarliaND
2013-12-01McMillanND
2014-01-01DalecarliaND
2014-01-01McMillanND
2014-02-01DalecarliaND
2014-02-01McMillanND
2014-03-01DalecarliaND
2014-03-01McMillanND
2014-04-01DalecarliaND
2014-04-01McMillanND
2014-05-01Dalecarlia0.300 ppb
2014-05-01McMillanND
2014-06-01Dalecarlia0.300 ppb
2014-06-01McMillanND
2014-07-01Dalecarlia0.400 ppb
2014-07-01McMillan0.300 ppb
2014-08-01Dalecarlia0.400 ppb
2014-08-01McMillan0.300 ppb
2014-09-01Dalecarlia0.500 ppb
2014-09-01McMillan0.300 ppb
2014-10-01Dalecarlia0.400 ppb
2014-10-01McMillan0.300 ppb
2014-11-01Dalecarlia0.300 ppb
2014-11-01McMillanND
2014-12-01DalecarliaND
2014-12-01McMillanND
2015-01-01DalecarliaND
2015-01-01McMillanND
2015-02-01Dalecarlia0.300 ppb
2015-02-01McMillanND
2015-03-01Dalecarlia0.300 ppb
2015-03-01McMillanND
2015-04-01Dalecarlia0.300 ppb
2015-04-01McMillanND
2015-05-01Dalecarlia0.300 ppb
2015-05-01McMillanND
2015-06-01Dalecarlia0.400 ppb
2015-06-01McMillan0.300 ppb
2015-07-01Dalecarlia0.400 ppb
2015-07-01McMillan0.300 ppb
2015-08-01Dalecarlia0.400 ppb
2015-08-01McMillan0.200 ppb
2015-09-01Dalecarlia0.400 ppb
2015-09-01McMillan0.300 ppb
2015-10-01DalecarliaND
2015-10-01McMillanND
2015-11-01DalecarliaND
2015-11-01McMillanND
2015-12-01DalecarliaND
2015-12-01McMillanND
2016-01-01Dalecarlia0.200 ppb
2016-01-01McMillanND
2016-02-01DalecarliaND
2016-02-01McMillanND
2016-03-01DalecarliaND
2016-03-01McMillanND
2016-04-01DalecarliaND
2016-04-01McMillanND
2016-05-01Dalecarlia0.200 ppb
2016-05-01McMillanND
2016-06-01Dalecarlia0.200 ppb
2016-06-01McMillanND
2016-07-01Dalecarlia0.300 ppb
2016-07-01McMillanND
2016-08-01Dalecarlia0.300 ppb
2016-08-01McMillan0.300 ppb
2016-09-01Dalecarlia0.400 ppb
2016-09-01McMillan0.300 ppb
2016-10-01Dalecarlia0.300 ppb
2016-10-01McMillan0.300 ppb
2016-11-01Dalecarlia0.300 ppb
2016-11-01McMillan0.200 ppb
2016-12-01DalecarliaND
2016-12-01McMillanND
2017-01-01DalecarliaND
2017-01-01McMillanND
2017-02-01DalecarliaND
2017-02-01McMillanND
2017-03-01DalecarliaND
2017-03-01McMillanND
2017-04-01DalecarliaND
2017-04-01McMillanND
2017-05-01Dalecarlia0.200 ppb
2017-05-01McMillanND
2017-06-01DalecarliaND
2017-06-01McMillanND
2017-07-01Dalecarlia0.300 ppb
2017-07-01McMillanND
2017-08-01Dalecarlia0.200 ppb
2017-08-01McMillanND
2017-09-01Dalecarlia0.400 ppb
2017-09-01McMillan0.300 ppb
2017-10-01Dalecarlia0.400 ppb
2017-10-01McMillan0.200 ppb
2017-11-01Dalecarlia0.200 ppb
2017-11-01McMillanND
2017-12-01Dalecarlia0.300 ppb