Heavy rain can overwhelm aging sewer systems, forcing tens of thousands of extra gallons of water through treatment plants—and in the worst-case scenario, causing untreated sewage to escape into the environment.
Graywater engineer Leigh Jerrard says, "Try to keep surface runoff and rainwater on your land and productively going into the water table." Use creative landscaping, such as rain gardens, berms, permeable pavement (i.e., no large concrete areas), and native plants instead of imported varieties. Here again, Jerrard says a graywater system offers benefits because it diverts thousands of gallons of water to plants instead of into the septic system.
Sandy Mason at The Illinois extension office recommends installing rain barrels to keep water from running off. "I am always amazed at how quickly a rain barrel fills after even a small storm." Mason says this water can be used on ornamental plants soon after it has been collected, but not on edibles, as harmful bacteria can multiply if the water sits in the barrel too long.