The Naper Settlement grounds feature 9,000 square feet of rain gardens. The Naper Settlement rain gardens contain plants native to Illinois, including pale purple coneflower, prairie blazing star, bee balm, butterfly milkweed, prairie drop seed, and little bluestem. The deep roots of these plants act like a sponge, helping storm water to soak into the ground instead of pooling on the surface and causing soil erosion and flooding. In addition to helping with water drainage, rain gardens also help to purify rainwater before it enters local water sources. The plants, sand, and soil work as a natural filter, removing dirt, toxins, and other chemicals from the water.