Most states grant governmental agencies broad immunity from tort liability when engaged in a governmental function, subject to enumerated statutory exceptions. Pleading around immunity, not merely alleging negligence, is what makes a claim viable.
Governmental function is generally defined expansively as any activity expressly or impliedly authorised by law, which means the immunity covers most of what a municipality does. Proprietary functions — activities conducted primarily for pecuniary profit and not normally supported by taxes — fall outside it.
Typical statutory exceptions. Defective highways and streets within the agency’s jurisdiction; negligent operation of a government-owned motor vehicle; dangerous or defective conditions in public buildings; sewage disposal system events; and medical care at government hospitals. Each has its own elements and notice rules.
Individual employees. Officers and employees are commonly immune for discretionary acts undertaken in good faith within the scope of authority, with a lower threshold — often gross negligence as the proximate cause — for the lowest tier of employees.
Pleading. In many jurisdictions immunity is not an affirmative defence but a characteristic of the claim, so the complaint must plead facts placing the case within an exception or it is dismissed.
Notice. Short statutory notice periods apply to several exceptions and are strictly enforced.