If you are representing a landlord in a rental transaction, you should work with the landlord to create written policies that are applicable to all applicants. If you intend to run a criminal background check on one applicant, you must run one on all applicants and notify them that they will be subject to a background check. Here are some considerations when referring to criminal background checks in rental applications: 

1.    You may never consider arrest records, only convictions.
2.    Limit your “look-back period” to 7-10 years. Again, make sure to have a written policy outlining your look-back period.
3.    People who have been convicted of crimes that affect the safety of people and/or housing may be denied on that basis.
4.    If possible, fall back on denying applicants based on their credit score or history rather than the criminal history.
 
And remember, even though individuals with criminal record histories are not in a protected class, you may face other claims of discrimination if you don’t have equally applied policies.