This paper presents the development and testing of a method to control electric water heaters (EWHs) to maximize their energy storage. The developed method is based on a bus-split (BS) aggregated model of EWHs and the unit commitment (UC). The BS aggregated model provides an accurate ON-OFF status of controlled EWHs, while the UC determines temperature settings for each controlled EWH to achieve maximum energy storage in that EWH. The ON-OFF status of EWHs is verified by the BS aggregate model at each time step to ensure following the temperature set by the UC. The BS-UC controller is implemented for performance evaluation using data collected from 150 households during the fall, winter, spring, and summer seasons. Test results demonstrate that the BS-UC controller can provide accurate, simple, and effective control of EWHs with minor sensitivity to the number aggregated EWHs, hot water consumption, parameters of EWHs, and seasonal variations of household power demands.