The City of Manitowoc's underground installations consist of 300 miles of mainline storm and sanitary sewers. Portions of the Sanitary Sewer system are cleaned daily as a preventative measure. In 1999 the division took responsibility for the maintenance of 15 sanitary sewer lift stations as well. The lift stations and sewers are maintained through a regular program of inspection and cleaning throughout the year. These maintenance expenses are funded by Sewer user fees collected through Utility billing.
The City has a separate Sanitary and Storm Sewer system. The City's stormwater system is permitted through the DNR as an MS4 system. This system includes the city's existing and proposed stormwater detention ponds as well as the city's street sweeping operations. The object of the permitting process is to reduce the city's impact on the waters of the state including Lake Michigan. More information about the City's stormwater management program can be found under Stormwater Management.