What is the Average Size and Placement of a Rain Garden?
A rain garden should have an area about 20% the size of the roof, patio, or pavement area draining into it. A typical residential rain garden is between 100 and 300 square feet. If a smaller rain garden than recommended for a lot is chosen, it will still function, as any size garden can make an impact. Rain gardens are longer than they are wide and are perpendicular to the slope, in order to catch the maximum amount of rainfall. Rain gardens should be placed at least 10 feet away from building foundations and should not be located where water ponds for an extended period of time.
