Michigan is known for elevated levels of naturally occurring arsenic in the groundwater.
The Department of Environmental Quality (DEQ), Office of Drinking Water and Municipal Assistance (ODWMA), in collaboration with Michigan’s Local Health Departments (LHDs), recommends that residents with wells have their well water tested for arsenic at a drinking water laboratory. Areas of elevated levels of arsenic in groundwater may occur over a few counties or be small and less defined.
Arsenic cannot be seen or tasted. A laboratory test is the only way to determine if water has high levels of arsenic.
The drinking water standard for arsenic at public water supplies is 10 parts per billion (0.010 milligrams per liter (mg/L)); this level or lower is generally considered safe to drink. While no action is required of homeowners whose well water is above this level, the DEQ recommends consuming bottled water or reverse‑osmosis‑treated well water if arsenic levels are above 0.010 mg/L.
Homeowners should not be concerned about bathing, laundering, or washing dishes with water that has elevated arsenic levels. Only consumption of arsenic is shown to be a health problem.
Homeowners that are served by a municipal water supply already receive water that meets the arsenic standard of 0.010 mg/L. Additional sampling is not recommended for these homeowners.
Please contact Sonja Warnock, Noncommunity and Private Drinking Water Supplies Unit, ODWMA, at 517-284-6542 for further information. You may also contact your LHD’s Environmental Health Office or check out our Arsenic Brochure.
To obtain arsenic water sample collection bottles, contact the DEQ’s Laboratory at 517‑335‑8184.