24 C.F.R. § 5.855
(a) You may prohibit admission of a household to federally assisted housing under your standards if you determine that any household member is currently engaging in, or has engaged in during a reasonable time before the admission decision:
(c) If you previously denied admission to an applicant because of a determination concerning a member of the household under paragraph (a) of this section, you may reconsider the applicant if you have sufficient evidence that the members of the household are not currently engaged in, and have not engaged in, such criminal activity during a reasonable period, determined by you, before the admission decision.