I was told I needed to fill out a rental application (where ssn is required) before viewing it because he gets several requests a day. It's legal yes and the authority is that landlords can run a background and credit check.□ Social Security number. All applicants must present a valid driver's license or other government-issued photo identification and one of the following: •. Ultimately, it is up to you as the landlord to determine whether or not you want to require a Social Security number on your rental application. Do you have to provide your Social Security number on the rental application? IMPORTANT: Please only submit ONE application per household. Be advised that if multiple applications are received, only the first one will.