Wanderlust World Wanderlust World Yes. Niagara Falls flows with freshwater from the Great Lakes system—the world's largest surface freshwater reservoir (21% of global supply).
Water path: Lake Superior → St. Marys River → Lake Huron → St. Clair River → Lake Erie → Niagara River → Falls → Lake Ontario → St. Lawrence River → Atlantic.
The Great Lakes are fed by precipitation, runoff, and groundwater—not seawater. Total dissolved solids in Niagara River water: ~150–200 mg/L (freshwater <1,000 mg/L; seawater ~35,000 mg/L).
The falls' volume averages 2,400 m³/s (85,000 ft³/s), split between Horseshoe Falls (90%), American Falls, and Bridal Veil Falls. Hydroelectric diversions reduce flow at night and off-season.