Short answer
Groundwater occupies saturated spaces below the land surface. Surface water is in rivers, lakes, wetlands and similar visible water bodies. Rainfall can recharge groundwater, and groundwater can feed streams, so these are connected parts of the water cycle rather than sealed supplies. 1 2
They differ by location and storage, but water can move between them through recharge and discharge.
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At a glance
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| Question | Groundwater | Surface water |
|---|---|---|
| Location | Below land surface | On land surface |
| Common access | Wells or springs | River or lake intake |
| Exchange | Can recharge and discharge | Can infiltrate or receive groundwater |
The table summarizes the cited definitions and the article’s stated scope. 1 2
What each thing is
Groundwater. Water in saturated pores and fractures beneath the ground surface. 1
Surface water. Water present on the land surface in rivers, lakes, wetlands and other open bodies. 2
Key differences
USGS emphasizes that many streams, wetlands and lakes exchange water with aquifers. A stream can lose water into the ground in one reach and gain groundwater in another. 1 2
How to tell them apart
Ask where the water is stored or flowing at the point of interest. A pumped well usually draws groundwater; a river channel contains surface water. For water-resource decisions, trace connections rather than assuming sources are independent. 1 2
Where they overlap
Both originate in the water cycle and can carry dissolved substances. The same water molecule may move from a river to an aquifer and later emerge from a spring. 1 2
Edge cases
A spring is groundwater emerging at the surface; after emergence it joins surface water. Shallow subsurface water may interact rapidly with a stream, blurring simple management boundaries. 1 2
Why the distinction exists
The location distinction is practical for measurement, regulation and supply planning, while recognizing exchange prevents one source from being managed in isolation. 1 2
Common misconceptions
Groundwater is generally in pores and cracks, not an underground lake. Surface water and groundwater do not always stay separate. 1 2
Examples
Water pumped from a permeable aquifer is groundwater. Water flowing in a creek is surface water, even if some of it recently came from that aquifer. 1 2
Sources
Sources checked October 3, 2026.
- USGS Water Science School — Groundwater: What is Groundwater?. What is groundwater?.
- USGS — Groundwater/Surface-Water Interaction. Integration of surface water and groundwater.