This paper presents the development of a water flow energy harvester (WFEH) designed to power smart water meters within residential piping systems. Utilizing the kinetic energy of flowing water, the device harnesses this energy and converts it into electricity via electromagnetic principles. The impeller's shape, quantity, and guide vane height at the inlet were simulated using computational fluid dynamics (CFD) software, comparing impeller rotational speeds under various simulation parameters to select the appropriate impeller configuration. Experimental data indicate that with an inlet water pressure of 0.12 MPa and an outlet pressure of 0.06 MPa, a single coil in the device generates a peak voltage of 3.6 V, with a peak power of 54.2 mW and a head loss of 6 m. The maximum head loss permitted in residential water pipes is 10 m. The energy generation module of the WFEH has been designed with a six-coil array, significantly enhancing its performance output. Theoretically, the output power of the WFEH is sufficient to meet the energy needs of smart water meters. Therefore, the WFEH holds potential for integration into urban water management systems, providing a stable energy supply for data collection and transmission, and contributing to the development of self-powered smart meters.