The North Jersey District Water Supply Commission serves about 2 millionconsumers from its 210 million gallons per day water treatment plant in Wanaque,New Jersey. Raw water is obtained primarily from the adjacent Wanaque Reservoir,and nearby rivers. Waste filter washwater and supernatant from cleaning thesettling basins is recycled to the head of the plant after passing through aholding/equalization basin. The Commission has been investigating alternatives tobetter handle these flows and improve finished water quality. One alternative isto treat the waste filter washwater and decanted settling basin supernatant withmicrofiltration (MF), and to use the microfiltered water as potable water or torecycle this water to the head of the plant. This paper presents the results ofpilot testing MF for this application and a preliminary engineering evaluation ofalternative plans. Includes tables, figures.