How to Become a Vendor

Washtenaw County utilizes a self-service portal that allows prospective vendors to create an online account and apply to be a vendor. The same portal allows vendors to view purchase orders and payment information. Please read our instructions for creating an account. The prospective vendor must register on our Vendor Self Service site and attach a W-9. Please pay attention to the instructions included in the documentation link above.

Modifying Information

Even though the self-service portal allows a business name change, a letter noting the change must be sent to Washtenaw County Accounts Payable on company letterhead. The letter must be signed by a principal of the company. 

Washtenaw County Accounts Payable
PO Box 8645
220 North Main St
Ann Arbor, MI 48107-8645

More Information

Learn about Doing Business with Washtenaw County, by reading our brochure (PDF).