Which wells are tested?

Many wells are regularly tested for 1,4-dioxane. See a map of testing locations.

Monitoring Wells

Pall Corporation currently has 257 monitoring wells. Monitoring wells are wells that were put in specifically to track the movement of the plume. Existing residential wells that are no longer used for drinking water are also used for monitoring. Monitoring wells are sampled at various times throughout the year. Some are tested monthly, while others are tested every three months, every six months, or once a year. No one drinks the water from these monitoring wells.

Homes & Businesses in the Plume Area

There are 34 drinking water wells at homes and businesses in the plume area that are tested every three months, every six months, or once a year, depending on location. Seven of these wells have tested positive for 1,4-dioxane at some point in their monitoring history. Of these seven wells, six have shown levels of 1 to 3 parts per billion (ppb) of 1,4-dioxane. These levels are less than the draft MDEQ drinking water criterion of 7.2 ppb. Only one well, serving a home and two businesses, tested above the new MDEQ draft drinking water criterion. This location was connected to city water in early March 2016. 1,4-dioxane has not been detected in the City of Ann Arbor’s drinking water.

  • In 2014, to be sure the plume wasn’t contaminating other drinking water wells, the MDEQ tested 90 additional wells at homes and businesses near the western edge of the plume. 1,4-dioxane was not detected in any of these samples.
  • In 2016, the MDEQ is planning to test another 38 wells north of the plume to be sure the plume has not impacted these water supplies. The results will be available on the MDEQ’s website for the project.

Show All Answers

1. What is 1,4-dioxane?
2. What can 1,4-dioxane do to my health?
3. How do I know if 1,4-dioxane is in my drinking water?
4. 1,4-dioxane has been detected in my well. What does the level mean?
5. Which wells are tested?
6. What if I want to test my water?
7. Is the a filter I can put on my faucet to remove 1,4-dioxane?
8. Can I use my well water for drinking?
9. Can I use my well water for bathing, washing hands, or laundry?
10. Should I be concerned about breastfeeding my child if I drink water with 1,4-dioxane?
11. Water comes into my basement. Do I need to worry about 1,4-dioxane in the water?
12. Can I use well water in my humidifier?
13. What if I want more information about the 1,4-dioxane plume?