The executive, administrative, judicial and legislative powers, authority and duties in such municipality shall be distributed into and among five departments, except that in municipalities having but three commissioners, three departments shall be designated and provided by the consolidation of the first and third departments and the fourth and fifth departments as follows:
1. Department of public affairs.
2. Department of revenue and finance.
3. Department of public safety.
4. Department of public works.
5. Department of parks and public property.