Ind. Code § 8-1.5-4-3
The department of waterworks has jurisdiction over a special taxing district (referred to as "the waterworks district" in this chapter) that consists of:
(2) in the case of any other municipality, all the territory within the corporate boundaries of the municipality, or the territory served by the waterworks if larger or smaller than the corporate boundaries.
As added by Acts 1982, P.L.74, SEC.1. Amended by P.L.12-1992, SEC.59; P.L.170-2002, SEC.60; P.L.119-2012, SEC.84; P.L.104-2022, SEC.60.