The Town of Lincoln, Massachusetts recently completed the design of a 1.6 million gallons per day (mgd) surface water microfiltration (MF) water treatment plant. The plant was required to comply with current and anticipated regulatory requirements. Because a MF plant for surface water was new to the Commonwealth of Massachusetts, there were several regulatory issues that needed to be addressed including: pilot testing requirements for membranes; technology acceptance; determination of removal credit; redundancy requirements; integrity testing requirements; and, backwash disposal. Approval from the Massachusetts Department of Environmental Protection (MDEP) was critical in order to proceed with implementing this facility. Because no regulations or guidelines for membranes existed in Massachusetts, the state had limited knowledge of and experience with membrane technology. This paper discusses how each issue was addressed and how the final design of a membrane treatment plant for this small community was completed in lieu of formal regulatory guidelines. Includes tables.