Upon completion of the inspection required by § 52.23, and upon receipt of a written report of the inspection, together with such photographs as may have been taken, the department of public works may, if satisfied that the sewer is free and clear of all foreign substance, and free of all engineering defects, approve the sewer. The department shall safekeep all inspection records and photographs for future reference by the city.
('69 Code, § 20-96)