Mendota Heights has a Municipal Separate Storm Sewer System (MS4) Permit with the State of Minnesota, administered by the Minnesota Pollution Control Agency. A MS4 is a network of drainage systems, city streets, catch basins, curbs, gutters, ditches, man-made channels, and storm drains that transport stormwater. A MS4 permit reduces the amount of sediment and pollutants entering state waters from stormwater systems.