The drainage district for a county drain is actually a public corporation.   It forms a special assessment district that is responsible for all costs on a drain project.   When a construction project is undertaken on a county drain, part of the process involves an apportionment of the costs.   That is, the Drain Commissioner must determine the proportionate share for each parcel of land within the drainage district and also for each municipality partially within the drainage district.   A day is set-aside for persons to review the apportionment and the procedure used in its determination.   An appeal of the apportionment is possible.

The total apportionment may be divided into annual payments.   If money is borrowed on the project, interest must also be added to the annual principal payments.

Project and maintenance costs are recovered through special assessments levied on private properties, local governments, county roads, railroads, and state highways.