Abstract
The water supply which coveres most part of Ishikawa prefecture began with the construction of Tedorigawa dam twenty years ago. Now this water provides water for sixteen municipalities out of forty-one in the prefecture. The object of this study is to consider the significance of the water supply which run outside Tedori River basin area by comparing supply-municipalities with non-supply-municipalities from the geographical point of view. In the severe drought in 1994, this water supply was of great help in supply-municipalities, where the water bill has been high.