(1) At any reasonable time, a representative of the department may enter in or upon any private or public property for the purpose of inspecting and investigating conditions relating to compliance with this part. However, an investigation or inspection under this subsection shall comply with the United States constitution, the state constitution of 1963, and this section.

    (2) The department shall inspect septage waste vehicles at least annually.

    (3) The department shall inspect a site at least annually.

    (4) The department shall inspect a receiving facility within 1 year after that receiving facility begins operation and at least annually thereafter.