Hydraulic network models are being used by a growing number of water company staff to answer an increasingly wide variety of questions. It is challenging to provide and maintain a series of accurate models suitable for all such applications. This discussion is based on the premise that an accurate, detailed model of the water distribution system represents a logical starting place for the automated generation of application-specific submodels. Model maintenance, to a large extent, then can be limited to this single model, or to the data sources from which it is derived. This paper discusses a set of automated data reduction and management tools developed to facilitate the customization of models to a desired level of detail. Data reduction, submodel extraction, model skeletonization, and model merging functions are explained and demonstrated. Specific applications are presented, including a detailed presentation of the positive impact one of these tools has had on the model maintenance efforts at the San Jose Water Company (SJWC).