(Wilsonville, OR)  --  Residents of Wilsonville and Sherwood are being asked to limit non-essential use of water.  One of four pumps at the Willamette River Water Treatment Plant failed on Friday.  A part to repair the pump is on order, but could take a week to arrive.  Residents are asked to limit outdoor irrigation, washing cars, and other non-critical uses of water.  The pump failure doesn't affect the quality of the water.