Water Valley is a home rule-class city in Graves County, Kentucky, United States. The population was 279 as of the 2010 census.
Water Valley is located at 36°34′0″N 88°48′39″W (36.566559, -88.810928).
According to the United States Census Bureau, the incorporated city has a total area of 0.6 square miles (1.6 km2), all land.
As of the census of 2000, there were 316 people, 141 households, and 90 families residing in the city. The population density was 508.0 people per square mile (196.8/km2). There were 166 housing units at an average density of 266.8 per square mile (103.4/km2). The racial makeup of the city was 94.94% White, 4.75% African American, 0.32% from other races. Hispanic or Latino of any race were 0.32% of the population.
There were 141 households, out of which 29.1% had children under the age of 18 living with them, 50.4% were married couples living together, 9.9% had a female householder with no husband present, and 35.5% were non-families. 34.8% of all households were made up of individuals, and 18.4% had someone living alone who was 65 years of age or older.