The Capacitance Resistance Model (CRM) is a model that is based on the material balance equation. It has been developed as early as the year 1943 and is proven to be a quick and reliable tool to provide rapid analysis for the prediction of reservoir performance. Multiple developments for CRM have been done for different applications, including the application of CRM in waterflooding, and modifying the CRM equations. In this study, the proxy-CRM by (Gubanova et al., 2022) will be applied to waterflooding case to determine the interwell connectivity between the injector – producer well during shut in period. The connectivity weight of the shut-in producer well will be modified into 0 and the connectivity itself will be added to a non-shut in producer well on the same period. To prove the accuracy and reliability of proxy-CRM on shut-in wells, two history matching cases are performed on a synthetic data and a field-scale synthetic simulation of UNISIM-I. Validation of both cases shows that the prediction is fast and accurate. When being compared to conventional CRMs, it also shows more realistic result.