Arsenic in Drinking Water

There are several ways you can be exposed to arsenic. Arsenic is a natural element found in some rocks and soils in Vermont and may get into groundwater. Every day you take in very small amounts of arsenic from air, water and food. Of these, food is usually the main source. This is generally because of the levels found in seafood and fish. But this form of arsenic is different than the arsenic in rocks and soil, and is not as harmful to your health. Arsenic is also found in consumer products and pressure treated wood.

Health Concerns: Is arsenic harmful to my health?

Health effects from drinking water with arsenic depend on two things:

  1. How much arsenic is in the water
  2. How many years you've been drinking the water

Drinking water with arsenic over a long period of time may cause an increased lifetime risk of bladder, lung or skin cancer. There also may be links to skin and cardiovascular diseases, diabetes or other cancers.

Testing: How do I know if arsenic is in my water?

You cannot see, smell or taste arsenic. Testing is the only way to know if arsenic is in your drinking water. The Health Department recommends testing your private water source for arsenic every five years.

Levels of arsenic in drinking water are regulated by the Environmental Protection Agency (EPA) and the State of Vermont. The drinking water standard for arsenic is 0.010 mg/L (milligrams per liter). Public water systems in Vermont that provide water to cities, towns, communities, schools, and workplaces must test on a set schedule and make sure the arsenic level is below this standard. Order a test kit for arsenic

Private well owners with arsenic levels at or above 0.010 mg/L should stop drinking the water and consider installing a treatment system to remove arsenic, drink bottled water instead, or get water from a known safe location.

Treatment Options: Can I remove or lower the levels of arsenic in my water?

Arsenic levels can be lowered in drinking water with treatment. Arsenic in water comes in two forms. Adsorptive filters and countertop distillation units remove both types.

Adsorptive Filters

As the water flows through the filter, arsenic sticks to the filter, which contains a type of granular iron oxide.

Countertop (plug-in) Distillation Units

These units boil water and then recondense the steam. The arsenic is left behind during this process, along with hardness and other minerals. These units can produce several gallons of arsenic-free water per day.

Some treatments require the water to go through an “oxidation” process first in order to change arsenic into a form that can be removed. Treatment system options for the second step are anion exchange, reverse osmosis and carbon block.

Anion Exchange Treatment

Anion exchange is a treatment like water softening, but uses a different media that exchanges the arsenic for chloride. This is installed as a whole house system (point-of-entry or POE).

Reverse Osmosis

This system uses a synthetic membrane that allows water to go through but leaves arsenic behind. The membrane is continually rinsed. This system is typically installed under a kitchen sink (point-of-use), but can also be installed POE system.

Carbon Block

This technology lowers total arsenic as the water passes through a solid carbon block. Look for National Sanitation Foundation (NSF) Standard 53 Certification, which verifies that the filter will remove arsenic.

Re-test for arsenic after any treatment system is installed to make sure levels are below the drinking water standard.