Accounts Payable (AP) disburses funds to pay supplier invoices and non-UW employees on behalf of UW departments, resolves any issues (also "exceptions") that may arise in the payment process through the invoice reconciliation procedure, and maintains compliance with state, university, and federal regulations. Most payments go through ARIBA.

Payment Methods

Depending on the payment method, the process may differ. 

  1. ARIBA PO Invoice
  2. ARIBA Non-PO Invoice
  3. ARIBA BPO Invoice
  4. Payments to Individuals (P2I)
  5. Wire Payments to Foreign Suppliers 
  6. eReimbursement
  7. Moving Expenses

Payment Terms

Standard payment terms for the UW are net 30 days from date of receipt of a properly completed invoice or goods, whichever is later. More information is available on the UW General Terms and Conditions page. Some contracts have specific payment terms so departments should reference the specific contract first.


Sales tax: applies to tangible personal property for those vendors subject to collect Washington State sales tax. As an example, if you purchase a chair from a local supplier or an out-of-state supplier who collect Washington State sales tax, you will be expected to pay the current tax rate. The out-of-state supplier will bill you the rate applicable at the point of delivery. A local supplier will bill the rate associated with the location of the delivery of the good purchased.

Use tax: application generally will effect transactions for out-of-state supplier transactions. As an example, when a chair is purchased from a vendor with no obligation to collect Washington State tax, the invoice will be for the selling price and shipping charge. 

Tax Exempt: If the item being purchased is deemed tax exempt, and the purchase is made with an out-of-state vendor, use tax should not be charged. 

Foreign Nationals

Federal law limits what payments can be made to a foreign national based on the type of visa the person holds. Additionally, the UW is liable for any tax not withheld on payments and the associated fines and penalties. It is critical that departments paying foreign nationals understand the department responsibilities and forms required for any payments.

Best Practices

  • ARIBA is supported through most major browsers, except for Internet Explorer in 64-bit mode and the Edge browser in Microsoft's new Windows 10 operating system.
  • If you are scanning paper records and attaching them in Ariba, you must follow the University Scanning Policy which can be found on the Records Management website.