In large brazilian urban centers, where there is a complexity of land-use planning, water supply becomes worrying due to factors such as population concentration, increased demand, diversity in the types of uses, unrestrained tubular well drilling, climatic changes, besides watercontamination. These factors, associated to the greater accessibility to well drilling technologies and inadequate groundwater management, hydrogeological studies was encouraged in certain regions that present high demands and evidence of an intense drawdown, such as in the Baquirivu-Guaçu River Basin - Guarulhos (Sedimentary Aquifer System), Bauru (Guarani Aquifer System), São José do Rio Preto (Bauru Aquifer System), São José dos CamposCaçapava-Jacareí (Taubaté Aquifer System), all in the Sao Paulo State. These areas are extremely dependent of groundwater, justifying the high number of existing wells. However, it was observed that about 70% of the registered wells do not have a concession, which could upset the adequate management of water resources. In this context of importance, and with the purpose of avoiding water collapses, the use of groundwater numerical modeling was highlighted as an important aid in the management of water resources, as it allows the understanding by the dynamics of complex hydrogeology systems, simulating future exploitation scenarios, and thereby enable important planning decisions to be made based on a well-defined technique. Fromtheresultsof the numerical model, well based on a conceptual model, it was possible to identify critical or potentially critical areas, which may require drilling restriction and indicate other areas more suitable for drilling new wells; or allow drilling in the critical area as long as the grant of the new well is conditional on monitoring and detailed studies. This requirement causes more data to be collected by improving the numerical modeling and knowledge of the aquifer, in addition to avoiding possible inadequate exploitation. The management decisions aim to minimize the cost of extraction and increase the benefits of groundwater, and these decisions may be related to the definition of pumping regime and well flow; the most appropriate location for the drilling of new wells; of incentive programs for use or restriction; of programs of benefits or financial compensation, control of land use, among others.