70 ILCS 605/4-9
Whenever the drains, levees or other work for the construction of which the district was organized are completed, then the appointing authority may, upon the petition of adult landowners owning a majority of the area embraced in the district, dispense with 2 commissioners, and the appointing authority shall thereafter appoint for such district a single commissioner, who shall hold office for a term expiring on the first Tuesday in September of the third year following his appointment and until his successor is appointed and has qualified, and such single commissioner shall perform the duties and be vested with and exercise the powers imposed upon commissioners generally. Whenever, upon the petition of one or more landowners in such district, it appears to the appointing authority that additional work may be necessary in such district, or for other good cause shown, the appointing authority shall appoint 2 additional commissioners in the manner provided by Section 4-10 so as to make a total of 3 commissioners for the district.
70 ILCS 605/4-9