Depends on how much ground you are talking about and where.
The total volume of readily available global groundwater is about 4.2 x 106 km3 Groundwater makes up about twenty percent of the world's fresh water supply, which is about 0.61% of the entire world's water, including oceans and permanent ice.
Hydrosphere
It equals exactly that, 34 cubic kilometres of water!What do you actually want to know?
3,100 cubic miles (mi3) or 12,900 cubic kilometers (km3)
41 million cubic kilometers, or, about 3%
2,434,000,000,000,000 (2.434 quadrillion) cubic meters, or 2.434 million cubic kilometers.
Earth has about 332.5 million cubic miles (1.386 billion cubic kilometers) of water, most of it in the oceans. The second largest volume of water is stored in glaciers and ice caps, followed by groundwater, lakes, soil moisture, atmosphere, and rivers.
1,310,000,000 cubic kilometers. Each cubic km = 264,172,052,360 gallons
1,382,400,000,000 gallons is about 5.2 billion cubic meters or 5.2 cubic kilometers (1.3 cubic miles). This is equivalent to a cube about 1.7 kilometers, or 1.1 miles on each side.
According to the U.S. Geological Survey, there is over 1,4 billion cubic kilometers of water on the planet. 95% of that water is in the oceans, so that makes 1,3 billion cubic kilometers of ocean water.
The amount of water vapor in the atmosphere varies from place to place. Humidity is the term used to describe the amount of water vapor in the atmosphere.
Earth's lakes contain approximately 176,400 cubic kilometers (about 42,000 cubic miles) of water. This represents a small fraction of the planet's total freshwater supply, with lakes holding around 20% of the world's surface freshwater. The majority of Earth's freshwater is found in glaciers and ice caps, while groundwater accounts for a significant portion as well.