The Delavan Lake Sanitary District was created in 1969 to operate and maintain a wastewater collection system serving properties adjacent to and surrounding Delavan Lake. Since 1997 the District has been responsible for the Aquatic Plant Management Program for Delavan Lake as well as various lake monitoring projects and studies in cooperation with Wisconsin DNR and USGS. Since 1995 DLSD has assisted the Town of Delavan in the monitoring lake levels and operation of the Delavan Lake (Borg) Dam facilities.
A direct function supplied by the DLSD in managing Delavan Lake Quality is the Aquatic Plant Harvesting! The harvesting crew harvested 3,845 yards of weeds which equates to 576.75 lbs of phosphorous.