Once petitioned, a "Board of Determination" convenes. The Board of Determination is a three-member board appointed by the Drain Commissioner. The members must be residents of the County but cannot own property in the Drainage District or in the Township/City/Village. The role of the Board of Determination is to receive testimony and evidence at a public hearing to determine:
- Whether a project is necessary and conducive to the public health, convenience or welfare
- Whether all or a portion of the project benefits the municipalities in the district for the protection of public health; and in some instances
- Whether lands should be included in or added to a drainage district.
The Board of Determination does not determine the scope of the project or the cost of the project, and does not determine how much property owners and municipalities will be assessed for the project. The Drain Commissioner makes these decisions after the engineering is performed, but before construction occurs.