Section 33-1314(B) of the Arizona Residential Landlord and Tenant Act states: "In the absence of a rental agreement, the tenant shall pay as rent the fair rental value for the use and occupancy of the dwelling unit."This rule extends to all people and not just formal tenants. So, for instance, if you invite a friend into your house to rent a room for $500 a month. Even without a written lease agreement you can evict that friend for non-payment of rent.
The "fair rental value" of an Arizona rental property can be disputed by reasonable people it is best to make sure that you have a written lease agreement in place before ever letting a tenant move into the property.
If you need help from an Arizona real estate attorney then call Clint Dunaway of the Dunaway Law Group at 480-389-6529 or email at firstname.lastname@example.org.