The Great Basin's rivers and lakes are primarily freshwater, though some areas have saline or alkaline conditions.

In the Great Basin, most rivers and lakes are freshwater, providing vital resources for the region’s ecosystems. While the region's arid climate causes high evaporation rates, many bodies of water in the Great Basin are still fresh, particularly at higher elevations. However, certain areas, such as the Great Salt Lake, have saline conditions. Freshwater sources in the Great Basin are crucial for sustaining plant life, wildlife, and providing habitat for migratory birds. These freshwater bodies are key to maintaining ecological balance in the region.