A method of de-watering during intermittent dry running periods with a self-priming centrifugal pump is presented. Centrifugal pumps, as opposed to diaphragm pumps, are advantageous because they are less expensive and can provide greater capacity. The shaft seals are sensitive, however, to frictional heating when water flow is interrupted. In some situations, this fractional heating may desiccate self-priming. The inventive concept provides a continuous stream of pressurized water moving through the pump to cool the seal and sustain priming capability without substantially impairing the ability of the pump to resume wet operation.