An oral irrigator including a fluid reservoir, a pumping assembly, a pressure control assembly, and a nozzle. The pumping assembly comprises a power source, a motor in electrical communication with the power source, and a pump in fluid communication with the reservoir. The pressure control assembly is in fluid communication with the pump; mechanically varies a pressure of a fluid exiting the nozzle to change the outlet pressure of the oral irrigator a high pressure to a low pressure and vice versa.