The distribution of water on the Earth's surface is extremely uneven. Only $3 \%$ of water on the surface is fresh; the remaining $97 \%$ resides in the ocean. Of freshwater, $69 \%$ resides in glaciers, $30 \%$ underground, and less than $1 \%$ is located in lakes, rivers, and swamps. Freshwater is water that contains little or no dissolved salt. Most freshwater is frozen in ice caps and glaciers.