This document provides a guideline for the selection of a proper grout material to repair water leakage through cracks and other deformities in concrete structures. The factors relevant to the quality control of maintenance and repair of water-leakage cracks are as the following; a) conditions of water-leakage cracks; b) performance requirements for repair materials; c) different types of repair materials (grouts); d) procedures followed to select the appropriate repair materials; e) execution of different types of repair methods; f) performance assessments of applied materials and methods; g) data collection. This document does not include any details on the repair of dry cracks and the causes of cracks. The details on dry crack repair are covered in ISO 16311-4. A flow chart for maintenance of water-leakage cracks is shown in Figure 1.