The systems and facilities that keep a city going are collectively known as public works. Hospitals, sewers, recycling, airports, schools — all of these are public works.
Public works are all of the public or municipal buildings and services in a town or city. The thing that makes them public is being government-funded and maintained by city or state taxes. They're also used by the general public: people send their kids to schools, put out their trash to be collected by city trucks, drive on roads maintained by the county, have picnics in public parks, and so on.