“No reported cases indicate whether a breach of an implied covenant of good faith may be raised as a defense to a residential unlawful detainer action [i.e., eviction]. Note, however, that a breach of the implied warranty of habitability may be so raised. See chap 15. It has been argued that the implied covenant of good faith requires a landlord to show just cause to evict a residential tenant. See Bell, Providing Security of Tenure for Residential Tenants: Good Faith as a Limitation on the Landlord's Right to Terminate, 19 Ga L Rev 483 (1985). If the landlord has breached the implied covenant of good faith, the tenant should consider raising that breach as an affirmative defense to the unlawful detainer action.
Because the courts have not yet decided whether the covenant of good faith applies in residential unlawful detainer actions, tenants must look to commercial lease cases for law concerning the covenant. Those cases have found an implied covenant. See §§19.20–19.24.”