What is a "Rain Garden"?
A rain garden is a garden that is designed to manage stormwater runoff. Think of it as wetland perennial garden or a small-scale water filtration plant right if you will. Rain gardens intercept rainwater on its way to the storm sewer making sure percolates into the ground to replenish the water table.
Easy for homeowners to design and build themselves, rain gardens are not much different than perennial gardens. They don't have to be mud holes or drab gardens filled with cattails and sedges although they certainly can be. There are many native wetland plants with beautiful flowers with interesting foliage and berries that thrive in moist to wet soils.
Most residential rain gardens range from 150 to 400 square feet in size and should be constructed on the low point of the property. The size of a rain garden is determined by calculating a percentage of the impervious surfaces on your property, for example the roof and driveway. The percentage is based on the type of soil. Water percolates quickly through sandy soils so the percentage, and ultimately the size of the rain garden is smaller than a property with predominantly clay soils. In fact, property owners with heavy clay soils might want to consider removing the clay layer and replacing it with sandy loam soils that allow better percolation.