70 ILCS 805/20
The board of commissioners of any forest preserve district whose boundaries encompass 2 or more municipalities may elect to be governed by all rules and regulations governing the construction and alteration of all buildings and structures and parts and appurtenances thereof as adopted by the county board of the county in which the district is located. The election to be governed by all such rules and regulations shall be made by adopting an ordinance to that effect. Within 30 days of adoption of said ordinance the forest preserve district shall notify each affected municipality by certified copy of said ordinance of its decision to be governed by the county's rules and regulations in such matters. The effective date of such ordinance shall be 60 days following its passage and approval by the board of commissioners.
70 ILCS 805/20