The purpose of this research is to develop a new planning tool to evaluate the efficiency of Low Impact Development (LID) for single-family homes in Ontario. A comprehensive literature review was conducted to compare major LID planning tool available for public to identify the key features of an ideal LID planning tool. A study across four regions in Ontario was conducted to obtain rainfall, soil, and housing-types data. U.S. EPA Stormwater Management Model (SWMM) was selected to perform all the simulation for establishing a common database for the new tool. With the new tool, users can estimate the runoff reduction, total suspended solids loading reduction, total phosphorus loading reduction and total cost by several clicks and few data inputs. The case study of Bayview Wellington Center in Town of Aurora illustrated that the new tool achieved required accuracy level.