The Iowa Great Lakes Sanitary District roughly covers an area from the Minnesota bored to the south end of Milford and alone the west side of West Okoboji and Spirit Lake and the east side of East Okoboji and Spirit Lake.  The Sanitary District also serves the cities of Orleans, Spirit Lake, Okoboji, Arnolds Park, West Okoboji, Wahpeton and Milford.  The Sanitary District also serves part of the areas in the unincorporated area.

To be served by the Sanitary District, a property must be annexed into the Sanitary District.  Many of the properties were brought in to the Sanitary District when it was formed back in the early 1950's through a public vote.  Since that time, properties have been able to annex in voluntarily or by annexation into a city that is part of the Sanitary District.  Iowa Code 358.26 Annexations, provides a process for involuntary annexation.