This paper investigates the symbiotic relationship between Heritage Building Information Modeling (HBIM) and Level of Information Need (LOIN) in the realm of heritage building management. Recognizing the generic nature of Level of Development (LOD) standards in HBIM, we underscore the significance of defining specific information requirements tailored to architects' needs. Employing the ISO 7817-1 standard as a guiding framework, our study focuses on the implementation of LOIN principles in a Moroccan heritage building for pathology diagnosis. First, a literature review on HBIM and LOIN is presented, a case study is illustrated and later results of a survey and interviews are analyzed and discussed. The paper is one of the first publications that shows how LOIN can be applied in HBIM for the erosion aspect of pathology analysis. Despite the current implementation of HBIM among architects in Morocco is very limited, the majority of interviews believes that the LOIN approach can improve effective definition of deliverables to drive more accurate conservation activities. To increase the HBIM maturity in the country, more training and fundings should be provided as well as collaboration between academia, industry and heritage organizations.