Ultrasonic water treatment is based on the ability of an ultrasonic device to induce cavitation in the liquid, generating physical and chemical effects that can be exploited to produce effective treatment. This require the device be capable of generating high amplitude pressure waves in a relatively large volume of water and biological inactivation within a realistic exposure period for the application. Most conventional ultrasonic devices fulfill only the first requirement, rendering such devices highly unsuitable for use in high-volume, high-flow liquid processes. In this report, the multiple orifice radial (MOR) resonator is proposed to overcome the said limitations by offering both high vibrational amplitude and large radiating area in a relatively compact assembly. This paper discusses the approach to the MOR resonator design and follow on with experimental measurements to characterize their dynamic characteristics. Results show that the vibrational amplitudes at the radiating surfaces of the radial resonators are comparable with conventional high-output ultrasonic probes. This demonstrates the high acoustic power capability of the MOR devices proposed.