Is there water inside Earth?
Yes. And the interesting part is not the answer — it is that the famous table of where all Earth’s water is stops before your question begins.
The source says so on the table’s own page
“But did you know that water is also inside the Earth?”
U.S. Geological Survey, “Water Science School — Where is Earth’s Water?”. Credit: U.S. Geological Survey.
The same page lists where water is, and slips the answer into the middle of the list:
“and inside the Earth in the top few miles of the ground”
U.S. Geological Survey, “Water Science School — Where is Earth’s Water?”. Credit: U.S. Geological Survey.
Read the end of that sentence again: the top few miles of the ground. That is not a throwaway phrase. It is the edge of what the table counts.
Where the counting stops
The whole table this site quotes is below, in the order the source publishes it. Most places show you the top row and maybe the rivers. The bottom is the part worth reading.
Oceans, seas and bays
1,338,000,000 km³
96.5%
Ice caps, glaciers and permanent snow
24,064,000 km³
1.74%
Groundwater, fresh and saline together
23,400,000 km³
1.7%
Fresh groundwater
10,530,000 km³
0.76%
Saline groundwater
12,870,000 km³
0.93%
Ground ice and permafrost
300,000 km³
0.022%
Lakes, fresh and saline
176,400 km³
0.013%
Soil moisture
16,500 km³
0.001%
Water in the atmosphere
12,900 km³
0.001%
Swamp water
11,470 km³
0.0008%
All the world's rivers
2,120 km³
0.0002%
Water inside living things
1,120 km³
0.0001%
Twelve rows, and the deepest thing in any of them is groundwater — the water in the soil and rock you could reach by drilling a well. Below that the table has nothing to say, because it was never counting that far down.
That is not a mistake by the people who made it. A measurement has an edge, and this one states where its edge is. What is unusual is how rarely anyone points at the edge when they show you the table.
One place where somebody does give a depth
The National Park Service, writing about the volcanoes of Alaska, describes water going down with a sinking slab of sea floor and coming back out much deeper than any well:
“When the Pacific Plate reaches a depth of approximately 100 km below the surface, the increased heat and pressure cause the oceanic crust to release water, which reacts with the surrounding rock to create magma, or liquid rock.”
U.S. National Park Service, “Volcanoes”. Courtesy of the National Park Service.
A hundred kilometres down. The table’s deepest row is a few miles. So there is certainly water far below where the counting stopped.
But notice exactly what that sentence is about. It describes one plate, sinking in one place, under Alaska. It is not a statement about the whole planet, and this page will not turn it into one by putting it next to a global table and hoping you join them up. Those are two different kinds of claim, and joining them is how a reader ends up believing something neither source said.
Where that water goes next is the subject of the page on where volcanic water comes from.
So how much is down there?
This site does not know, and it is not going to guess. There are numbers in circulation for how much water is locked inside the rock of the deep Earth, and they come from research papers arguing with each other — not from the kind of source this site builds on. Putting one here would mean copying a figure without being able to show you where it came from or how sure anyone is of it.
So the honest shape of the answer is: yes, there is water inside Earth; the best-known table counts it down to a few miles and then stops; and one national park service will tell you about water a hundred kilometres down beneath one particular place. Everything past that is a question this site has not yet earned the right to answer.
The water itself is much older than any of this counting. That page has the numbers.
Where this comes from
- The quotations and the table
- U.S. Geological Survey, “Water Science School — Where is Earth’s Water?”, read . That page publishes no date of its own, so the copy this site quotes is pinned by its checksum instead of by a version number. The twelve figures come from the USGS global distribution table, transcribed with each row’s own published wording. The depth is U.S. National Park Service, “Volcanoes”, last updated December 9, 2019. Material created by both agencies is in the public domain, and every quotation here is checked against the page it came from, word for word, each time this site is built.
- How sure is this?
- The table is one published estimate and says so on its face; the figures are reproduced as it publishes them and nothing here is recalculated. The Alaska depth is a single agency’s statement about a single plate boundary and is not treated as a global figure. Nothing on this page rests on a reconstruction, and the one thing a reader will most want — a total — is deliberately absent rather than estimated.