The City of Ann Arbor Water Treatment Plant has taken voluntary steps to enhance the removal of per- and polyfluoroalkyl substances (PFAS) from drinking water.


GAC filters in treatment plant

In September 2018, the Ann Arbor City Council voted to replace the current granular activated carbon (GAC) in all of the city’s filters with a new type of GAC that is more effective at removing both types of PFAS that have been given lifetime health advisory levels of 70 parts per trillion (ppt) by the U.S. EPA. While concentrations of these two compounds in the city’s drinking water maintained an average concentration of 7 ppt in 2018 and have never exceeded the advisory levels, the city has taken the initiative to exceed federal guidance standards and install the best available technology for municipal water treatment.

The city began piloting the new filtration technology in fall 2017. The new technology was successful at removing PFOS and PFOA to non-detectable levels during the first nine months following installation. The city expects to expand the technology to all its filters by spring 2019. After the project is completed, the city anticipates that concentrations of PFOS and PFOA will be reliably less than 10 ppt. 

In 2018, the city was awarded a grant by The Water Research Foundation to continue to study and refine techniques to remove PFAS compounds from drinking water. The city is currently testing new filters prior to full-scale implementation. Detailed testing plans are currently being developed and should be finalized in early 2019. This research project is expected to conclude in 2021.