This document is Deliverable 7.3 of the Co-UDlabs project, funded under the European Union’s Horizon 2020 research and innovation programme and under Grant Agreement No 101008626. This report is aimed at academic researchers, water utility engineers and R&D engineers in the pipe repair supply chain who need to (i) understand the impact of defects on pipe performance, and (ii) to provide evidence on the effectiveness and robustness of different in-pipe repair technologies. In-pipe defect surrogates have been employed in academic research studies and applied research studies that have been used to develop in-pipe repair technologies (e.g. cured-in-place-pipe pipe repair systems) and validate then to objectively measure the performance of different repair technologies. This allows water utilities to make evidence based decisions on what repair technology to adopt. Suitable in-pipe defect surrogates are also required in the development of emerging in-pipe inspection technologies. This report describes a range of in-pipe surrogate defects that are mapped against the EN 13508-2, which is the EN that is widely used in Europe to characterise the range of specific defects commonly found in sewers and urban drainage systems. The report describes how surrogate defects are mapped against EN 13508-2 defect codes. The development of the surrogate defects has involved significant technical input from water utilities, to ensure acceptance of the laboratory defects as effective surrogates for similar defects observed in real sewer and drainage pipes. The report also describes how the laboratory defects can be manufactured so allowing laboratories to manufacture consistent defects that have been accep0ted by water utilities as being appropriate surrogates for typical in-pipe defects that have been mapped onto the most widely accepted defect coding system. The report offers advice to laboratories about how to select defects from this report, with a strong emphasis that any study needs to clarify its aim so that a suitable laboratory surrogate defect is selected for each study.