Government inspections of homes and businesses are searches, and the requirement of a warrant applies with modifications.

Administrative warrants may issue on a showing less than criminal probable cause — a reasonable legislative or administrative standard for conducting an inspection, such as an area-wide plan based on the passage of time, the nature of the building or the condition of the area.

Consent. Valid consent obviates the warrant, and much routine inspection proceeds on it. Consent must be voluntary, and conditioning a license on blanket prospective consent is constitutionally doubtful.

Closely regulated industries. A narrow category permits warrantless inspection under a regulatory scheme that provides a constitutionally adequate substitute for a warrant: a substantial government interest, inspections necessary to further the scheme, and a program certain in scope and regularity that limits inspectors’ discretion.

Emergencies. Genuine exigency permits immediate entry.

Pretext. An administrative inspection used as a cover for a criminal investigation is invalid, and evidence obtained may be suppressed. Where inspectors develop criminal suspicion, the practice is to stop and obtain a criminal warrant.

Municipal practice. Written inspection policies with neutral criteria, training on consent and refusal, and a standard administrative warrant application form are the controls that keep enforcement admissible.