What is 1,4 Dioxane?

1,4 dioxane is a solvent and is listed by US EPA as a probable carcinogen. It should not be confused with dioxin, a known carcinogen. Technical information is available on-line at the US Environmental Protection Agency. http://www.epa.gov/ttn/atw/hlthef/dioxane.html

Is there 1,4 Dioxane in the City of Ann Arbor’s drinking water?

No. No observable level of 1,4 Dioxane is, or ever has been detected to-date in Ann Arbor’s municipal drinking water supply. Tests are frequently applied to the source water brought into the Water Treatment Plant as well as the water supplied to our customers.

Has the City ever detected 1,4 Dioxane in any Ann Arbor drinking water source?

Yes. During a routine test in 2001, a trace level of 1,4 Dioxane (1-2 ppb/parts per billion) was detected in water from Ann Arbor’s Northwest Supply well, which was used by the city as a water source during the winter months. The Northwest Supply well water was not being used at the time of the positive test and was immediately closed and remains closed. The Northwest Supply well provided less than 5% of Ann Arbor’s total source water.

How can I learn more about Ann Arbor’s drinking water quality?

The Ann Arbor Water Utility provides an Annual Water Quality Report to municipal customers, including test results that demonstrate our drinking water consistently meets or exceeds all Federal water quality standards. The most recent report, and more water quality information, is available on the web at http://www.ci.ann-arbor.mi.us/Utilities/WTP/int-lab.html .