水源

Refers to the physical point where water emerges from the ground or the starting point of a river. While it is often used in geographical contexts, it also encompasses any source of water used for human consumption or industry, such as aquifers or reservoirs.

It is distinct from the word 源流 (genryū), which specifically refers to the headwaters or the very beginning of a river's flow. 水源 is a broader term that includes any "source" of water, including wells and springs, and is frequently used in administrative, environmental, and engineering contexts (e.g., water resource management).

In modern usage, it often appears in discussions regarding environmental conservation and the prevention of pollution to ensure a stable supply of clean water for populations.