24 CFR § 247.6 - Eviction.
(b) Limitations on allegations of new grounds. In any judicial action instituted to evict the tenant, the landlord must rely on grounds which were set forth in the termination notice served on the tenant under this subpart. The landlord shall not, however, be precluded from relying on grounds about which he or she had no knowledge at the time the termination notice was sent.
(c) State and local law. A tenant may rely on State or local law governing eviction procedures where such law provides the tenant procedural rights which are in addition to those provided by this subpart, except where such State or local law has been preempted under part 246 of this chapter or by other action of the United States.