This is a really great question! According to the US Geologic Survey earthwherewater about 97.5% of the water on Earth’s surface is salt water (in the oceans or salty lakes). That leaves only 2.5% that is fresh water. Of that, about 69% is frozen fresh water in glaciers and ice caps, 30% is groundwater (water in cracks of rocks and in pore-space of sediments like sand and clay), and only about 1% in surface water in lakes, rivers, and in the atmosphere. That means that most fresh water near the surface of the earth is in glaciers and in the ground. I found this interesting bar graph on the USGS website:

There is another important reservoir of water in the earth... rocks! Certain types of minerals that make up rocks can hold a lot of water in their crystal structure. In the earth’s crust, minerals like mica and amphibole contain a lot of water (up to several percent of the weight of these minerals is “water”). The mantle of the earth (the part that is between the core and the crust) is composed of minerals that are mostly “dry” (they contain very little water). However, the mantle reservoir is so big that one study estimates that the mantle contains an large amount of water equal to 40–85% of the volume of the oceans (Bell & Rossman, 1992)!

references
Bell, D.R. & Rossman, G.R. (1992). Water in earth’s mantle: The role of nominally anhydrous minerals. Science, 255, p. 1391–1397.

Around 68% of the freshwater on Earth is in the form of glaciers and ice caps. Another 30% or so is locked up in the ground, and the last couple percent of freshwater can be found in ground ice, lakes, rivers, swamps, and the atmosphere.

Most of our earth's fresh water is in glaciers and polar ice caps. These are big frozen blocks of ice on the tops of mountains and in the arctic and antarctic. The second biggest source of freshwater is underground. This is how most cities get their water, by drilling water wells into the ground and pulling out the water.

The last source of water is in lakes and rivers, but this is actually one of the smallest sources! This water only makes up about 2-3% of all freshwater -- the rest is either in the glaciers or underground.

Most of Earth's fresh water is locked away in the polar caps. Most of the rest is ground water.

Well, there are three main sources of fresh water: groundwater, the water in lakes and rivers and the water tied up in the solid state as ice.

As you can see most of the 'fresh' H₂O is tied up in glaciers as ice, then comes groundwater. Very little water is in lakes and rivers.