Dive Deep into Earth's Waters: 2026 Earth Science Splashdown Practice Test!

Saltwater makes up the vast majority of Earth's water because the oceans hold most of it. About 97% of all Earth's water is saline and resides in the oceans, seas, and other saltwater bodies. The remaining roughly 3% is freshwater, but much of that is tied up in glaciers and ice caps, with only a small portion readily accessible in rivers, lakes, and groundwater. This distribution explains why, even though Earth has a lot of water, only a tiny share is suitable for drinking and irrigation.