Depends on the size- Duties of household manager depends on the size of the house. Big house consist of so many of duties like cleaning, maintaining and much more so you need to keep this thing in mind.
Keep the house shiny- Number one aim of the household manager is to keep the house shiny and that cannot be done by the members in the house.
Keep everything maintained- Everything should be maintained in the house and this is the job of the household manager.
