When necessary to investigate a suspected violation of this land use code, or an application for or revocation of any permit issued under this land use code, the city manager may enter on any site or into any structure open to the public for the purpose of investigation, provided entry is done in accordance with law. Absent a search warrant, no site or structure that is closed to the public shall be entered without the consent of the owner or occupant. No owner or occupant or agent thereof, shall, after reasonable notice and opportunity to comply, refuse to permit entry authorized by this section. If entry is refused, the city manager shall have recourse to the remedies provided by law to secure entry.