Group B Public Water Systems - Arsenic

Arsenic in Drinking Water

What is arsenic and where does it come from?

Arsenic occurs naturally in the earth's crust. Most arsenic in drinking water comes from natural rock formations. As water flows through these formations, it can dissolve arsenic and carry it into underground aquifers, streams, and rivers that may supply drinking water. Arsenic also can come from human activities, such as mining or smelting ores that contain arsenic, and arsenic was once used in commercial wood preservatives and agricultural chemicals.

How can I find out if there's arsenic in my drinking water?

Arsenic is tasteless and odorless. If you haven't done so already, we recommend Group B water system owners test each groundwater supply twice - once in the summer and once in winter to account for seasonal fluctuations.Use a certified lab to perform the analysis.

NOTE: If you search for labs that test for arsenic by using "search for analyte," make sure you select a lab that tests drinking water.

Does arsenic affect human health?

Yes. Low levels of arsenic in drinking water, soil, air, and food pose a slight health risk. Like most contaminants, the more you are exposed to over time, the greater the risk of experiencing health effects. Arsenic health effects include diseases that can affect the cardiovascular system, kidneys, skin, nervous system, or lead to various forms of cancer. If you are worried about long-term consumption of water with high levels of arsenic, consult your physician. There are tests that can help your doctor determine how much arsenic is in your body.

What is the maximum contaminant level for arsenic in drinking water?

Effective January 1, 2014, the drinking water standard for arsenic will be 10 ppb.

Do some parts of Washington have more arsenic than others do?

Yes. Elevated levels of naturally occurring arsenic have been found in parts of Washington. Scientists attribute these higher arsenic levels to the geologic composition of these locations. Here is a state map that shows where high levels of arsenic have been found.

Should I boil my water if it has high levels of arsenic?

No. Boiling water does not remove arsenic.

Can I remove arsenic from my drinking water?

Yes. Several treatment methods will effectively remove arsenic from drinking water. You should work with an experienced consulting engineer to determine the best treatment method to use.

If your water comes from a privately owned well, you should select a treatment method certified by a recognized third-party testing organization. These third-party organizations list only treatment methods that meet strict testing protocols established by the American National Standards Institute (ANSI) and NSF International.

Remember, even these products may not be effective in all cases. We recommend that you continue to have your water tested after installing this equipment and that you keep the equipment well maintained.

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