No person shall be found in violation of this article unless the public officer, after a reasonable inquiry and inspection of the premises, believes that conditions exist of a quality and appearance not commensurate with the character of the neighborhood. Such belief must be supported by evidence of a level of maintenance significantly below that of the rest of the neighborhood. Such evidence shall include conditions declared unlawful under § 8-308, but shall not include conditions that are not readily visible from any public place or from any surrounding private property.