Banks Lake South is a census-designated place (CDP) in Grant County, Washington, United States.

[4] Banks Lake South is located in northern Grant County adjacent to the eastern border of Coulee City.

It is on the east side of Banks Lake near its southern end, part of the Upper Grand Coulee valley.

26.7% of all households were made up of individuals, and 6.7% had someone living alone who was 65 years of age or older.

About 4.3% of families and 8.7% of the population were below the poverty line, including 14.3% of those under the age of eighteen and 8.8% of those 65 or over.