Janesville is part of the Rock River Stormwater Group. It is a city located in Rock County in southern Wisconsin and has a population of 63,575. Janesville is known to be “Wisconsin’s Park Place.” The Rock River runs right through Janesville. For more information about Janesville’s stormwater, go to http://www.ci.janesville.wi.us/government/departments-divisions/public-works/engineering-division/stormwater-greenbelt-management-information.