Know Your Environment. Protect Your Health.

Arsenic

City of Tacoma

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.

 

20

Samples

0

Samples exceeding legal limit (MCL)

6

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20180.150 ppb21ND - 0.300 ppb
2019ND10ND
2020N/A00N/A
20210.467 ppb62ND - 1.70 ppb
20220.300 ppb82ND - 1.30 ppb
20230.333 ppb31ND - 1.000 ppb

ppb = parts per billion

State, National, and Health Guidelines for Drinking Water

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
2018-02-07ND
2018-10-180.300 ppb
2019-12-05ND
2021-06-2141362961.10 ppb
2021-06-214136297ND
2021-06-2141363001.70 ppb
2021-06-214136298ND
2021-06-304143413ND
2021-07-214159325ND
2022-09-1543711971.10 ppb
2022-10-114371889ND
2022-11-1543845331.30 ppb
2022-12-274400688ND
2022-12-274400688ND
2022-12-274400688ND
2022-12-274400688ND
2022-12-274400688ND
2023-07-124499687ND
2023-07-1244996891.000 ppb
2023-10-204549137ND