Sec. 4. (a) This section applies to:
(1) a sewer;
(2) a sewage disposal plant or installation; or
(3) a storm water drain;
that is installed by a district in and serves an area that subsequently comes within the corporate limits of a municipality that is not a part of the district.
(b) The municipality may purchase that part of the sewage disposal works or storm drainage system with approval of the court and agreement with the district. The district shall protect the district's own operations and obligations.