Residency Requirements. The Registrar Office must determine your legal residency before you can register and pay fees for any semester or session.Please note: Students also may be required to complete a Residency Affidavit. This form must be submitted in person if you are a resident of Pima County. Residency in Pima County is a requirement of county subsidized medical care. PRIMARY RESIDENCE DEFINITION: A Primary Residence is your one and only main residence where you or a qualified family member resides. Step 1: Complete the online application: Apply to Pima. Current F-1 Students. Have questions about your F-1 status? You can register immediately upon becoming a resident.