Stormwater begins as rain or snowmelt that flows over land rather than seeping into the ground. It flows over hard surfaces (impervious surfaces) such as roofs, driveways, and walkways, as well as pervious surfaces such as grass, gardens, and woodlands into the city’s combined sewer system. The more hard surface (impervious surface) on your property, the more stormwater runoff is contributed to the sewer system.
This drainage flows into the same underground pipes as sewage and must be treated at the Great Lakes Water Authority (GLWA) wastewater treatment plant before it can be released back into the environment.
The City of Royal Oak is billed by the Oakland County Water Resources Commissioner for the conveyance and treatment of combined sewage at GLWA.
Pervious Surface versus Hard Surface