catchment area

noun

1. an area served by a hospital, social service agency, etc.
2. drainage basin.

noun

1. Also called: catchment basin, drainage area, drainage basin the area of land bounded by watersheds draining into a river, basin, or reservoir
2. the area from which people are allocated to a particular school, hospital, etc

1. The area drained by a river or body of water.
2. The area that absorbs water that contributes to a specific region’s groundwater supply.