A sump pump can run longer when heavy rain or groundwater is filling the pit quickly. If it keeps running after the water level falls, the float or switch may be stuck. If the pit stays full, the discharge line may be blocked or the pump may not be moving enough water. The exact cause depends on the pump and installation.
Check the water level and look for an obvious obstruction only if the area is dry and safe. Do not handle plugs or electrical parts while standing in water. If the pump will not shut off or the water is rising, request sump pump service promptly.