This paper explores the integration of terrestrial laser scanning (TLS) and unmanned aerial system (UAS) photogrammetry for the diagnosis and evaluation of deformations in industrial tanks, demonstrating their significant contribution to preventive maintenance. TLS accurately measures distances to the tank’s surface, generating detailed 3D point clouds, while UAS photogrammetry captures high-resolution images from various angles and altitudes. By combining TLS and UAS data into comprehensive 3D models, engineers can identify subtle deformations and anticipate structural failures. The study results revealed significant deviations in tank shell verticality and roundness using TLS and notable roof unevenness using UAS. Comparing 3D models before and after corrective measures showed improved structural integrity. This approach enhances safety, optimizes resources, and enables targeted interventions. The findings highlight the potential of TLS and UAS technologies to revolutionize preventive maintenance, offering an efficient, precise, and less intrusive methodology for critical infrastructure inspection. Adopting these technologies can improve safety, reduce operational risks, and optimize asset management in various industrial sectors.