Pay by Phone: To pay your water bill by phone, have your 12 digit water billing account number and call 844.395.2242. There is no extra service charge to pay by phone. Pay by Mail: You can mail your water bill payments with a check to: Dept # 77610 City of Ann Arbor Treasurer P.O. Box 77000 Detroit, MI 48277-0610 Please make sure to include the bill stub or full account number on check. Drop Boxes: Drop boxes are available 24-hours a day on the north side of the City Hall, 301 E. Huron, Ann Arbor, MI 48104 located on the corner of East Ann St and North Fifth Ave (Gray mail box) as well as in the building, just inside the Ann Street entrance. These payments will be processed the next business day. Pay In Person: You can make payments in person at the City of Ann Arbor Customer Service & Payment Center located within Larcom City Hall, 301 E. Huron, Ann Arbor, MI 48104. Business hours are Monday through Friday 7:30 a.m. to 5:30 p.m. (except holidays).